研究者詳細 - 河内　俊憲

論文 - 河内　俊憲

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Spherical shock wave modulation induced by interaction with homogeneous isotropic turbulence

K. Tanaka, T. Watanabe, H. Suzuki, T. Kouchi

Physics of Fluids 2025年2月

CNN Model to Predict Wall Shear Stress From Flow Velocity Data Without Viscous Sub-Layer

Kazuki Naridomi, Toshinori Kouchi, Kento Tanaka

AIAA Scitech2025 2025年1月

Investigation of Instantaneous Velocity-Fields by Schlieren Image Velocimetry Using Ray-Traced Simulated Focusing-Schlieren Images

Toshinori Kouchi, Narumi Kodera, Kento Tanaka, Hiroki Suzuki

AIAA Scitech2025 2025年1月

Numerical Analysis of a Low Reynolds Number Flow in a Non-Contact Air Stage Validated through Time Increment Width Testing 査読

Hiroaki Oka, Hiroki Suzuki, Jun Fujiwara, Toshinori Kouchi

Proceedings of the 12th JFPS International Symposium on Fluid Power P2-21 2024年10月

Attempt to compensate for effects of energy conservation error on static pressure fluctuation using sub-grid scale components with the Reynolds number dependence of isotropic/anisotropic steady turbulence 査読

Makoto Chitose, Hiroki Suzuki, Toshinori Kouchi

Journal of Physics: Conference Series 2793 ( 1 ) 012004 - 012004 2024年7月

掲載種別：研究論文（学術雑誌）出版者・発行元：IOP Publishing

Abstract

This study focuses on the kinetic energy conservation error and the compensation effect by adjusting a model constant. The kinetic energy conservation error is caused by the implicit time integration of the second-order Crank-Nicholson method, and we investigate how much this error affects the RMS of the static pressure fluctuation. Anisotropic and isotropic external force terms are used to generate a steady turbulent flow field, and the numerical analysis employs Large Eddy Simulation (LES) and the Smagorinsky model. Studies have shown that the influence of kinetic energy conservation errors on turbulent kinetic energy is limited, but large-scale turbulent structures are affected by errors in anisotropic turbulent fields with large Re numbers. Ta. Regarding the compensation of the RMS of the static pressure fluctuation, it was shown that the error could be reduced in both isotropic and anisotropic fields by adjusting the model constant, but there was a clear difference for the turbulent kinetic energy. This result shows that the compensation of kinetic energy conservation errors by a model constant is not perfect and that the errors can have different effects on the turbulence statistics.

DOI： 10.1088/1742-6596/2793/1/012004

その他リンク： https://iopscience.iop.org/article/10.1088/1742-6596/2793/1/012004/pdf

Numerical analysis clarifying non-equilibrated periodic flows generated by dual-scaling Taylor’s analytical solution 査読

Xuanyou Gong, Hiroki Suzuki, Toshinori Kouchi

Journal of Physics: Conference Series 2793 ( 1 ) 012001 - 012001 2024年7月

掲載種別：研究論文（学術雑誌）出版者・発行元：IOP Publishing

Abstract

This study investigates the properties of a flow field derived from the multiplexed Taylor solution, focusing on its impact on established equilibrium relationships. We numerically analyse a multiplexed flow field by introducing a secondary flow with twice the period of the original Taylor solution, hypothesising that this dualisation affects the balance between transient and viscous terms. The visualisation of the flow field and the time evolution of the kinetic energy are investigated. Using second and sixth order central differences and the fractional step method with BiCGStab, we analyse three flow fields with different coefficients in a two-dimensional periodic domain. The study shows that the dualisation of the flow field disturbs the equilibrium between the unsteady and viscous terms. The time-averaged kinetic energy shows that the evolution of the dualised field approaches the kinetic energy distribution of the analytical solution, with variations depending on the coefficient of the quadratic term. The spatial distribution of the kinetic energy in fully developed fields is also compared with the analytical solution.

DOI： 10.1088/1742-6596/2793/1/012001

その他リンク： https://iopscience.iop.org/article/10.1088/1742-6596/2793/1/012001/pdf

LES Analysis on the Impact of Mass Conservation Uncertainty on the Static Pressure Fluctuation in Spatially Periodic Steady Turbulence 査読

Xuanyou Gong, Hiroki Suzuki, Mikio Nakahama, Toshinori Kouchi

2023 2nd International Conference on Automation, Robotics and Computer Engineering (ICARCE) 1 - 5 2024年4月

CTA Measurement on the Frequency Response of a Grid Turbulence Fluctuation Measurement with a Focus on Bispectrum 査読

Hiroto Yamaguchi, Hiroki Suzuki, Kyosuke Fujita, Toshinori Kouchi

2023 2nd International Conference on Automation, Robotics and Computer Engineering (ICARCE) 1 1 - 6 2024年4月

Non-linear response of kinetic energy in an inviscid Taylor-Green flow obtained by OpenFOAM-LES with respect to time increments 査読

Akira Ono, Hiroki Suzuki, Toshinori Kouchi

Journal of Physics: Conference Series 2701 ( 1 ) 012054 - 012054 2024年2月

掲載種別：研究論文（学術雑誌）出版者・発行元：IOP Publishing

Abstract

This study investigates the conservation error of kinetic energy with respect to time increment using OpenFOAM LES. The energy conservation error is verified using an inviscid Taylor-Green vortex and the effect on energy conservation is checked by varying the time increment by a factor of 30. Differences in the response of turbulent energy conservation between large and small time increments are also verified. Higher order accuracy for time increments is expected when the kinetic energy conservation accuracy is high, however the actual behaviour in OpenFOAM needs to be investigated: as the implicit time integration method is used in OpenFOAM, a non-linear response is expected. As a result, it is evident that kinetic energy is not fully conserved in the inviscid flow of OpenFOAM. The kinetic energy distribution is similar for different time increments, with a different relationship between the conservation error observed in the range of large and small time increments.

DOI： 10.1088/1742-6596/2701/1/012054

その他リンク： https://iopscience.iop.org/article/10.1088/1742-6596/2701/1/012054/pdf

Energy conservation uncertainly due to the use of an implicit time integration method clarified by a multiplexed TGV inviscid flow 査読

Makoto Chitose, Hiroki Suzuki, Toshinori Kouchi

Journal of Physics: Conference Series 2701 ( 1 ) 012059 - 012059 2024年2月

掲載種別：研究論文（学術雑誌）出版者・発行元：IOP Publishing

Abstract

This study attempts to elucidate the conservation errors induced by the implicit time integration method within a multiscale flow. Using the multiplexed Taylor analytical solution as the initial field, three distinct multiscale turbulence fields were formulated, each characterised by different wavenumber attributes. A two-dimensional inviscid flow field, replicated in a computational domain with a side of 2π and subject to periodic boundary conditions, was used to illuminate kinetic energy conservation errors. The implicit time integration method - specifically the second-order accurate Crank-Nicolson method - was compared with explicit methods, such as the second-order accurate Adams-Bashforth and third-order accurate Runge-Kutta methods. The study also examines the differences between the analytical Taylor solution and a random flow field, particularly in their satisfaction of the Navier-Stokes equations and wavenumber composition, while highlighting the need for preliminary analysis for random flow fields prior to validation calculations.

DOI： 10.1088/1742-6596/2701/1/012059

その他リンク： https://iopscience.iop.org/article/10.1088/1742-6596/2701/1/012059/pdf

Multiscaled inviscid Taylor-Green vortex flow for examining energy conservation error in incompressible flows 査読

Xuanyou Gong, Hiroki Suzuki, Toshinori Kouchi

Journal of Physics: Conference Series 2701 ( 1 ) 012052 - 012052 2024年2月

掲載種別：研究論文（学術雑誌）出版者・発行元：IOP Publishing

Abstract

This study investigates kinetic energy conservation errors in incompressible flows using multiplexed inviscid Taylor-Green vortices. Fourth-order precision Runge-Kutta methods, specifically five- and six-step methods, were employed and an inviscid two-dimensional periodic flow field was used as a test case. This method allows the energy conservation error to be suppressed to a very low level. Recent previous studies have dealt with turbulence generation using a multi-scale turbulence grid. In this study, the Taylor-Green vortex of the analytical solution is multiplexed to generate a flow field with a number of wavenumbers. Visualisation results of the initial field and the energy distribution over time were obtained. It was observed that the errors in the time evolution of the fluid energy were extremely small, and that the errors actually increased with time. However, the influence of the time step range was limited and the analytical and numerical solutions were in general agreement. As a result, it was confirmed that the inviscid Taylor-Green vortex is effective in examining the energy conservation error for incompressible flows.

DOI： 10.1088/1742-6596/2701/1/012052

その他リンク： https://iopscience.iop.org/article/10.1088/1742-6596/2701/1/012052/pdf

Experimental validation on a calibration position of a hot-wire anemometer for measuring multi-scale grid-generated turbulence 査読

Hiroto Yamaguchi, Hiroki Suzuki, Toshinori Kouchi

Journal of Physics: Conference Series 2701 ( 1 ) 012056 - 012056 2024年2月

掲載種別：研究論文（学術雑誌）出版者・発行元：IOP Publishing

Abstract

This study aims to experimentally examine conditions that should be satisfied by a calibration position of a constant-temperature hot-wire anemometer. Specifically, this study addresses an appropriate measurement point when this calibration is performed downstream of a turbulent field generated by a multi-scale turbulence grid. The hot-wire measurement in this study is based on an I-type probe with a standard 5 μm tungsten wire. The hot-wire anemometer in this study is small and can be attached to a probe support. In this study, uncertainty in the calibration curve of the hot-wire measurement is first checked. Here, Pitot tube velocimetry to obtain the calibration curves is carried out using two bell-type micro-differential pressure gauges. Then, the characteristics of the obtained velocity fluctuations and turbulence will be examined. Based on this relative velocity fluctuation RMS value, the effects of the obtained streamwise velocity fluctuation on output voltage are obtained by asymptotically expanding a calibration curve. Using these results, the intensity of the free-stream turbulence, which has a negligible effect on output voltage giving a calibration curve, is clarified.

DOI： 10.1088/1742-6596/2701/1/012056

その他リンク： https://iopscience.iop.org/article/10.1088/1742-6596/2701/1/012056/pdf

LES analysis of local isotropic turbulence depending on the spatial scale of the external forcing field 査読

Koki Minami, Hiroki Suzuki, Toshinori Kouchi

Journal of Physics: Conference Series 2701 ( 1 ) 012055 - 012055 2024年2月

掲載種別：研究論文（学術雑誌）出版者・発行元：IOP Publishing

Abstract

The study investigates the effect of the parameterisation of an external force scheme based on trigonometric functions on turbulence. In particular, the dependence of the generated turbulence on the Reynolds number and the influence of its spatial parameters are investigated. The turbulence used is generated by a large-eddy simulation based on a high-precision finite volume method, and the turbulence energy and isotropy of the turbulence are also investigated. The parameter of the external force field used in this study characterises the wavelength of the trigonometric function, and the influence of this parameter on the spatial scale is studied in detail. As a result, steady turbulent fields are generated and isotropic turbulence is observed at different spatial scales of the external force field with M=2, 3 and 4. The property of increasing turbulence energy with increasing Reynolds number is confirmed.

DOI： 10.1088/1742-6596/2701/1/012055

その他リンク： https://iopscience.iop.org/article/10.1088/1742-6596/2701/1/012055/pdf

Locally Broken Shock Wave Detection with One-Dimensional Convolutional Neural Network in Shock Turbulence Interaction

Kento Tanaka, Toshinori Kouchi, Hiroki Suzuki, Koichi Takeuchi

AIAA SCITECH 2024 Forum 2024-2340 2024年1月

Phase-lock Analysis of Two-Dimensional Transonic Shock Buffet by Using Machine Learning

Tsubasa Kikuchi, Toshinori Kouchi, Kento Tanaka, Koichi Takeuchi

AIAA SCITECH 2024 Forum 2024-0905 2024年1月

Assessing OpenFOAM-based Large-eddy Simulation Using Decay Characteristics of An Isotropic Taylor-green Vortex 査読

Akira Ono, Makoto Chitose, Hiroki Suzuki, Toshinori Kouchi

Journal of Physics: Conference Series 2694 ( 1 ) 012004 - 012004 2024年1月

掲載種別：研究論文（学術雑誌）出版者・発行元：IOP Publishing

Abstract

The aim of this study is to investigate OpenFOAM using isotropic TGV flows. The main focus is on the establishment of energy conservation laws, in particular using inviscid fields to assess energy constancy; Large-Eddy Simulation (LES) is applied and the results are compared with those obtained using spectral methods; unlike previous studies of OpenFOAM, this study uses an unsteady turbulent TGV flow. The computational methods used are a central difference method, a PISO algorithm and a Smagorinsky model. The study revealed errors in the conservation of kinetic energy in the OpenFOAM analysis. In particular, the energy decay was significant at high spatial resolution, confirming the different turbulence energy decay characteristics of DNS and OpenFOAM. However, when the model constant was 0.6, the decay characteristics were shown to be in good agreement with DNS.

DOI： 10.1088/1742-6596/2694/1/012004

その他リンク： https://iopscience.iop.org/article/10.1088/1742-6596/2694/1/012004/pdf

Comparative Testing the Uncertainty of A/D Converters in A Hot-Wire Anemometer Measurement Using Grid-Generated Turbulence 査読

Hiroto Yamaguchi, Hiroki Suzuki, Toshinori Kouchi

Journal of Physics: Conference Series 2694 ( 1 ) 012003 - 012003 2024年1月

掲載種別：研究論文（学術雑誌）出版者・発行元：IOP Publishing

Abstract

This study investigates the uncertainty of the A/D converter when measuring multi-scale turbulence fluctuations using a hot-wire anemometer. The flow is generated in a low-speed wind tunnel, the turbulence is generated by a turbulence grid and the fluctuations are measured. A compact hot-wire anemometer was used and a high accuracy A/D converter was introduced for the measurements. Methods to minimise the influence of noise were also incorporated and measurements were carried out in two situations, one with and one without turbulence. The experimental results showed that measurements under a specific condition (Case 1 in this study) had the sufficienty reproducibility of turbulence fluctuations and the least effect of noise. The results showed that the high frequency characteristics of the turbulence could also be accurately measured under this condition. In conclusion, it is clear that the choice of a suitable A/D converter and the optimisation of the measurement environment are critical for turbulence measurements with a hot-wire anemometer.

DOI： 10.1088/1742-6596/2694/1/012003

その他リンク： https://iopscience.iop.org/article/10.1088/1742-6596/2694/1/012003/pdf

Fundamental numerical analysis clarifying the response of incompressible turbulence fields to the uncertainty of kinetic energy conservation 査読

Makoto Chitose, Hiroki Suzuki, Kento Tanaka, Toshinori Kouchi

Proceedings of the International Conference on Power Engineering 2023 (ICOPE-2023) ICOPE-2023-1274 2023年5月

Examination of multi-scale generated decaying turbulence validated for the influence of wind tunnel blockage 査読

Hiroto Yamaguchi, Hiroki Suzuki, Kento Tanaka, Toshinori Kouchi

Proceedings of the International Conference on Power Engineering 2023 (ICOPE-2023) ICOPE-2023-1268 2023年5月

Dynamic Mode Decomposition of Simultaneous Dual-layer Focusing Schlieren and Unsteady Pressure-Sensitive Paint Measurements for Transonic Buffet on a Swept Wing

Shota Fukumoto, Toshinori Kouchi, Yosuke Sugioka, Shunsuke Koike

AIAA SCITECH 2023 Forum 2023-1180 2023年1月

Experimental comparison of shock buffet on unswept and 10-deg swept wings 査読

Yosuke Sugioka, Toshinori Kouchi, Shunsuke Koike

EXPERIMENTS IN FLUIDS 63 ( 8 ) 2022年8月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER

Shock wave oscillations and surface flow fields on unswept-wing and 10 deg swept-wing models were experimentally investigated in a two-dimensional transonic wind tunnel facility to clarify the effects of wing sweep on the shock buffet phenomena. High-speed shadowgraph imaging, oil flow, and unsteady pressure-sensitive paint (PSP) techniques were used to visualize the shock oscillation over the models, surface stream lines, and the surface pressure distributions, respectively. Shock waves oscillated periodically on both models under specific flow conditions, but the oscillation frequency for the 10-deg swept wing was 1.4 times higher than that for the unswept wing. A spectral analysis and a mode decomposition analysis of PSP data for the 10 deg swept-wing model showed that higher-frequency shock oscillation developed mainly on the outboard wing, where a complicated 3D surface flow structure was formed. We confirmed that the wing sweep angle is an important factor affecting characteristic Strouhal number of shock buffet according to the present data and the results of previous studies.[GRAPHICS].

DOI： 10.1007/s00348-022-03482-x

Impact of Pitot tube diameter on the centre line mean flow velocity in multi-scale grid-generated turbulence 査読

Hiroto Yamaguchi, Hiroki Suzuki, Kento Tanaka, Toshinori Kouchi

Journal of Physics: Conference Series 2313 ( 1 ) 012001 - 012001 2022年7月

Development of a single-scale initial flow field into steady homogeneous turbulence with validating a constructed Fourier spectral analysis 査読

Hiroki Suzuki, Toshinori Kouchi

Journal of Physics: Conference Series 2313 ( 1 ) 012008 - 012008 2022年7月

掲載種別：研究論文（学術雑誌）出版者・発行元：IOP Publishing

Abstract

This study presents the development of a single-scale initial velocity field into steady homogeneous isotropic turbulence. Here, we verify a constructed Fourier spectral analysis, which is then used to approach the present issue. The present homogeneous isotropic turbulence is maintained steady by using a linear forcing scheme of Lundgren (2003). Here, two values of the primary coefficient are set here for this scheme. The initial velocity field is also set to maintain the flow globally isotropic. Temporal developments of turbulence statistics, visualization results and structure functions are examined in this study. As shown in a previous study, Rosales and Meneveau (2005), the turbulence length scale at a steady-state could remain independent of a value used for the linear forcing coefficient. The turbulence fields needed 10 to 15 times longer than the turbulence time scale to achieve this steady-state. A larger amount of time was needed for the structure functions to reach their steady-state profiles than for the turbulence statistics.

DOI： 10.1088/1742-6596/2313/1/012008

その他リンク： https://iopscience.iop.org/article/10.1088/1742-6596/2313/1/012008/pdf

Side-Wall Effects on the Global Stability of Swept and Unswept Supercritical Wings at Buffet Conditions

Andrea Sansica, Atsushi Hashimoto, Shunsuke Koike, Toshinori Kouchi

AIAA SCITECH 2022 Forum 2022年1月

動的モード分解を用いた二次元翼バフェットの主要モードの抽出査読

福本翔太, 河内俊憲, 大寺健吾, 杉岡洋介

日本航空宇宙学会論文集 70 ( 3 ) 82 - 92 2022年

Existence of dual solutions and three-dimensional instability in helical pipe flow 査読

Anup Kumer Datta, Toshinori Kouchi, Yasutaka Hayamizu, Yasunori Nagata, Kyoji Yamamoto, Shinichiro Yanase

Chinese Journal of Physics 73 154 - 166 2021年10月

Sea-Level Static Tests of Rocket–Ramjet Combined Cycle Engine Model 査読

Sadatake Tomioka, Masao Takegoshi, Toshinori Kochi, Kanenori Kato, Toshihito Saito, Kouichiro Tani

Journal of Propulsion and Power 37 ( 3 ) 381 - 390 2021年5月

Influence of Partial Electrical Conducting Wall on Electrodynamic Flow Control 査読

NAGATA Yasunori, YAMANE Eisuke, NORII Takumi, KOUCHI Toshinori, YANASE Shinichiro

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN 19 ( 1 ) 68 - 74 2021年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES

The electrodynamic flow control effect using an applied magnetic field has a potential of innovative technology for aerodynamic force control of atmospheric entry vehicle because of no requirement of mechanical devices. To control this effect and aerodynamic force, we proposed a new approach using exposed electrodes on the vehicle surface. If the induced electric current is bypassed via exposed electrodes, the electromagnetic field could be changed. In this study, the influence of the partial electrical conducting wall, which is consisted of insulating and conducting walls, is numerically investigated. As a result of the MHD simulation, flow field could be changed by the vehicle surface condition. Especially, in the frontal region of the vehicle where strong Lorentz force acts, if the conducting wall is installed to electrically short to the shoulder position, the electric field within this region and the electrodynamic effect is significantly changed. Additionally, stepwise drag variation could be made by selectable shorted electrodes.

DOI： 10.2322/tastj.19.68

LESを用いた超音速乱流場における垂直噴流の混合

青木礼, 河内俊憲, 田中健人, 鈴木智也

数値流体力学シンポジウム講演論文集(CD-ROM) 35th 2020年1月

LES Analysis of Transverse Jet Mixing in Supersonic Free-stream Turbulence

Yasunori Nagata, Seitaro Yokoi, Rei Aoki, Toshinori Kouchi, Shinichiro Yanase

AIAA Scitech 2020 Forum 2020年1月

Numerical Study of the Lift Force, Velocities and Pressure Distribution of a Single Air Bubble and Two Interacting Air Bubbles Rising in Quiescent Liquid 査読

Chao Guan, Shinichiro Yanase, Koji Matsuura, Toshinori Kouchi, Yasunori Nagata

Open Journal of Fluid Dynamics 10 ( 01 ) 31 - 51 2020年

Numerical study of air-entraining and submerged vortices in a pump sump 査読

Shinichiro Yanase, Ryo Yamasaki, Toshinori Kouchi, Shunsuke Hosoda, Yasunori Nagata, Higuchi Shunji, Toshihiko Kawabe, Toshihiro Takami

IOP Conference Series: Earth and Environmental Science 240 ( 3 ) 032001 - 032001 2019年3月

Acetone-condensation nano-particle image velocimetry in a supersonic boundary layer

Toshinori Kouchi, Seiya Fukuda, Syouma Miyai, Yasunori Nagata, Shinichiro Yanase

AIAA Scitech 2019 Forum AIAA 2019-1821 2019年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：American Institute of Aeronautics and Astronautics

© 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. Condensation nanoparticle planar laser light scattering imaging was conducted in a suction type Mach 1.9 supersonic flow. A series of the nanoparticle image pair was obtained by using the same optical components of PIV. The velocity data were obtained by the image pairs using the image-based correlation procedure as same as PIV. Acetone vapor instead of tracer particles in a conventional PIV was added to a mainstream gas in a reservoir. Acceleration process through a Laval nozzle automatically generated condensation particles of the acetone which were uniformly seeded into the entire flowfield. The increase in the additive concentration increased the number density of the particle and enabled a detail visualization of the vortex structures in the boundary layer. The increase in the additive concentration also increased the mean molecular weight of the acetone-seeded air. This decreased the flow speed. However, this is not a big matter because the heat release due to the condensation was negligible and the decrease in the flow speed was easily predicted from the thermodynamic properties of the gas. The particle size was difficult to be measured directly, so the tracer response time was estimated by the oblique shock test. The Stokes diameter of the particle was estimated to be 160 nm. Such a small diameter particle provides high traceability resulting in capturing shock wave with a few vector spacing and also provides high spatial resolution image resulting in capturing sub-mm scale vortices within the boundary layer. The mean and turbulent velocity fields evaluated from such high spatially and temporally resolved image pairs fairly agreed with previous measurement in the boundary layer.

DOI： 10.2514/6.2019-1821

Hydrodynamic instability with convective heat transfer through a curved channel with strong rotational speed

Mohammad Sanjeed Hasan, Rabindra Nath Mondal, Toshinori Kouchi, Shinichiro Yanase

AIP Conference Proceedings 2121 2019年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：AIP Publishing

In this paper, a comprehensive numerical study on viscous incompressible fluid flow and heat transfer through a loosely coiled square duct has been presented. Spectral method is used as a basic tool to solve the system of non-linear partial differential equations. Numerical calculations are carried out for the Dean number Dn = 1000 with a temperature difference across the vertical sidewalls for the Grashof number Gr = 100, where the outer wall is heated and the inner wall cooled. A rotation of the duct about the center of curvature is imposed in the positive direction for the Taylor number 0 <= Tr <= 2000 and combined effects of the centrifugal, Coriolis and buoyancy forces are investigated. First, steady solutions are obtained by the Newton-Raphson iteration method. As a result, three branches of asymmetric steady solutions with two- to four-vortex solutions are obtained. Then, time evolution calculations as well as power spectrum density of the unsteady solutions are obtained and it is found that the unsteady flow undergoes through various flow instabilities, if Tr is increased in the positive direction. Nusselt numbers are calculated as an index of convective heat transfer, and it is found that convective heat transfer is significantly enhanced by the secondary flow. Finally, a comparison between the numerical and experimental investigations has been provided. It is found that there is a good agreement between the numerical and experimental investigations.

DOI： 10.1063/1.5115851

VSL解法の電磁ヒートシールド解析への拡張査読

永田靖典, 石原遼一, 前田真吾, 河内俊憲, 柳瀬眞一郎

日本航空宇宙学会論文集 67 ( 1 ) 16 - 24 2019年

記述言語：日本語出版者・発行元：一般社団法人日本航空宇宙学会

<p>The electrodynamic heat shield is new type of heat protection system for atmospheric-entry vehicle, which utilizes the Lorentz force acting on the weakly ionized plasma flow inside the shock layer. A huge amount of calculation is necessary to estimate overall effect of the electrodynamic heat shield, because its effect interacts with the atmospheric-entry trajectory. In the present study, the Viscous Shock Layer (VSL) analysis method for electrodynamic heat shield is proposed for the quick analysis, which can calculate much faster than Navier-Stokes (NS) simulation. For this purpose, the VSL equations for the electrodynamic heat shield analysis are introduced under the ideal gas assumption, including circumferential momentum equation and Maxwell equations. The new method is also proposed to solve the new VSL equations. By the comparison to the NS simulation, the new VSL method gives good estimations of drag force and wall heat flux for wide ranges of interaction parameter and Hall parameter although the slight difference of wall heat flux at the stagnation point is observed. Therefore, the present VSL method could be applicable to the estimation tool of the electrodynamic heat shield effect. </p>

DOI： 10.2322/jjsass.67.16

CFD Simulation of an Ejector-jet Engine 査読

Hiromu Inoue, Toshinori Kouchi, Yasunori Nagata, Shinichiro Yanase

Asia-pacific International Symposium on Aerospace Technology 2019 APISAT-733 2019年

静止流体中の鉛直壁面近傍を上昇する単一球形気泡の修正Force-coupling Methodによる数値解析査読

関超, 柳瀬眞一郎, 松浦宏治, 河内俊憲, 永田靖典

ながれ : 日本流体力学会誌 = Nagare : journal of Japan Society of Fluid Mechanics 37 ( 3 ) 281 - 289 2018年6月

LES Investigation of Supersonic Mixing Layer Using Different Type of Gas

Tatsuya Kishi, Toshinori Kouchi, Yasunori Nagata, Shinichiro Yanase

Asian Joint Conference on Propulsion and Power 2018 AJCPP2018-035 2018年

Laminar forced convective heat transfer in helical pipe flow 査読

Anup Kumer Datta, Shinichiro Yanase, Toshinori Kouchi, Mohammed M.E. Shatat

International Journal of Thermal Sciences 120 41 - 49 2017年10月

Numerical Study of Turbulent Helical Pipe Flow With Comparison to the Experimental Results 査読

Anup Kumer Datta, Yasutaka Hayamizu, Toshinori Kouchi, Yasunori Nagata, Kyoji Yamamoto, Shinichiro Yanase

Journal of Fluids Engineering 139 ( 9 ) 2017年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ASME International

Turbulent flow through helical pipes with circular cross section is numerically investigated comparing with the experimental results obtained by our team. Numerical calculations are carried out for two helical circular pipes having different pitches and the same nondimensional curvature δ (=0.1) over a wide range of the Reynolds number from 3000 to 21,000 for torsion parameter β (=torsion /2δ = 0.02 and 0.45). We numerically obtained the secondary flow, the axial flow and the intensity of the turbulent kinetic energy by use of three turbulence models incorporated in OpenFOAM. We found that the change to fully developed turbulence is identified by comparing experimental data with the results of numerical simulations using turbulence models. We also found that renormalization group (RNG) k−ε turbulence model can predict excellently the fully developed turbulent flow with comparison to the experimental data. It is found that the momentum transfer due to turbulence dominates the secondary flow pattern of the turbulent helical pipe flow. It is interesting that torsion effect is more remarkable for turbulent flows than laminar flows.

DOI： 10.1115/1.4036477

Extracting dominant turbulent structures in supersonic flow using two-dimensional Fourier transform 査読

Toshinori Kouchi, Goro Masuya, Shinichiro Yanase

Experiments in Fluids 58 ( 8 ) 2017年8月

Effect of Torsion on the Friction Factor of Helical Pipe Flow 査読

Datta Anup Kumer, Yanase Shinichiro, Hayamizu Yasutaka, Kouchi Toshinori, Nagata Yasunori, Yamamoto Kyoji

Journal of the Physical Society of Japan 86 ( 6 ) 064403 - 064403 2017年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：The Physical Society of Japan

Three-dimensional direct numerical simulations of a viscous incompressible fluid flow through a helical pipe with a circular cross section were conducted for three Reynolds numbers, <italic>Re</italic>(= 80, 300, and 1000), and two nondimensional curvatures, δ (= 0.1 and 0.05), over a wide range of torsion parameters, β (= nondimensional torsion/<inline-formula><tex-math version="MathJax"><![CDATA[\(\sqrt{2\delta } \)]]></tex-math></inline-formula>), from 0.02 to 2.8. Well-developed axially invariant regions were obtained where the friction factors were calculated, in good agreement with the experimental data obtained by Yamamoto et al. [<ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1016/0169-5983(95)00022-6" xlink:type="simple">Fluid Dyn. Res. <bold>16</bold>, 237 (1995)</ext-link>]. It was found that the friction factor sharply increases as β increases from zero, then decreases after taking a maximum, and finally slowly approaches that of a straight pipe when β tends to infinity. It is interesting that a peak of the friction factor exists in the region 0.2 ≤ β ≤ 0.3 for all the Reynolds numbers and curvatures studied in the present paper, which manifests the importance of the torsion parameter in helical pipe flow.

DOI： 10.7566/jpsj.86.064403

Modified Lee’s Transonic Buffet Mechanism Inspired with Fast-framing Focusing-schlieren Visualization

Toshinori Kouchi, Shingo Yamaguchi, Yuki Yamashita, Shinichiro Yanase, Shunsuke Koike

55th AIAA Aerospace Sciences Meeting 2017年1月

Supersonic Combustion using Multiple Stinger-shaped Injectors 査読

KOUCHI Toshinori, TOMIOKA Sadatake, HIRANO Kohshi, MATSUO Akiko, MASUYA Goro

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES 60 ( 1 ) 56 - 59 2017年

OpenFOAMを用いたポンプ水槽内に発生する空気吸込渦と水中渦の解析査読

山崎諒, 河内俊憲, 永田靖典, 柳瀬眞一郎

日本機械学会論文集 83 ( 853 ) 17 - 00181-17-00181 2017年

記述言語：日本語出版者・発行元：一般社団法人日本機械学会

<p>Numerical prediction of air-entraining and submerged vortices in pump sumps is important for engineering applications. The validation of pump sump simulations, however, still is not enough, because the simulations is very complicated; for examples, treatment of gas-liquid interface, detection method of the vortices and selection of turbulence model etc. We conducted numerical simulations of the benchmark experiments of the pump sump conducted by Matsui et al. (2006, 2016) and compared the simulation with the experimental data to investigate the effects of turbulence model, grid density and detection method of the vortices. We determined a threshold of the gas-liquid fraction function of VOF method (α) and the second invariant of velocity gradient tensor (Q₂) to detect the air-entraining and submerged vortices by using vorticity, respectively. This method well detected the vortices and well reproduced the experiments for the RANS simulation using SST k-ω model. Large eddy simulation using Smagorinsky model, however, was sensitive to the grid system and difficult to reproduce the experimental vortex structures even for the finest grid system having 3.7 million cells.</p>

DOI： 10.1299/transjsme.17-00181

マイクロフォンアレイを用いた枚葉式半導体洗浄装置内に形成される大規模渦構造の検出査読

河内俊憲, 三好勇輝, 中野裕介, 永田靖典, 柳瀬眞一郎

日本機械学会論文集 83 ( 845 ) 16 - 00441 2017年

Application of the Modified Force-Coupling Method of Tracing the Trajectories of Spherical Bubbles with Solid-Like and Slip Surfaces 査読

Chao Guan, Shinichiro Yanase, Koji Matsuura, Toshinori Kouchi, Yasunori Nagata

Open Journal of Fluid Dynamics 07 ( 04 ) 657 - 672 2017年

Optimization of Focusing Schlieren System for an Axisymmetric Ejector 査読

Masato Nakaya, Toshinori Kouchi, Yasunori Nagata, Shinichiro Yanase

11th Pacific Symposium on Flow Visualization and Image Processing PSFVIP11-055 2017年

Combined Fast-framing Schlieren Imaging and Stereo PIV Measurements in a Supersonic Boundary-layer 査読

Mayu Mizoguchi, Kazuki Yamauchi, Toshinori Kouchi, Yasunori Nagata, Shinichiro Yanase

9th JSME-KSME Thermal and Fluids Engineering Conference TFEC9-1463 2017年

Wavelet analysis of transonic buffet on a two-dimensional airfoil with vortex generators 査読

Toshinori Kouchi, Shingo Yamaguchi, Shunske Koike, Tsutomu Nakajima, Mamoru Sato, Hiroshi Kanda, Shinichiro Yanase

Experiments in Fluids 57 ( 11 ) 2016年11月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Springer Science and Business Media LLC

We visualized the shock buffets on a two-dimensional transonic airfoil with and without vortex generators (VGs) by using a fast-framing focusing schlieren imaging. The focusing schlieren visualization showed that the flow three-dimensionality around the airfoil became remarkable with installing the VGs. This implies that narrow depth of focus of imaging systems was a key to accurately capture the characteristics of the shock oscillation due to the buffet for the cases with VGs. The time-resolved imaging also revealed that non-periodic components were included in the shock oscillation due to the buffet for the cases with VGs. This prevented Fourier analysis from being applied. We used wavelet analysis to extract the characteristic of the shock oscillation for the cases with VGs. The wavelet spectrograms revealed that the low-frequency oscillation having the buffet frequency was still included intermittently in the shock oscillation even when VG controlled the buffet. The rate of appearing the low-frequency oscillation increased with increasing both the interval between VGs and the angle of attack.

DOI： 10.1007/s00348-016-2261-2

その他リンク： http://link.springer.com/content/pdf/10.1007/s00348-016-2261-2.pdf

Wavelet Analysis of Unsteady Shock-wave Motion on Two-dimensional Airfoil with Vortex Generators

Toshinori Kouchi, Shingo Yamaguchi, Shunsuke Koike, Shinichiro Yanase, Tsutomu Nakajima, Mamoru Sato, Atsushi Kanda

54th AIAA Aerospace Sciences Meeting 2016年1月

Development of DEM–CFD Simulation of Combustion Flow in Incinerator with the Representative Particle Model 査読

Kenya Kuwagi, Toshihiro Takami, Azri Bin Alias, Degang Rong, Hiroshi Takeda, Shinichiro Yanase, Toshinori Kouchi, Toru Hyakutake, Kaoru Yokoyama, Yoshiyuki Ohara, Nobuo Takahashi, Noritake Sugitsue

Journal of Chemical Engineering of Japan 49 ( 5 ) 425 - 434 2016年

Turbulent diffusion flux of transverse jet into pseudo-shock wave

Taekjin Lee, Toshinori Kouchi, Yoshinori Oka, Goro Masuya

54th AIAA Aerospace Sciences Meeting AIAA 2016-0662 2016年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：American Institute of Aeronautics and Astronautics

© 2016, American Institute of Aeronautics and Astronautics Inc, AIAA. All Rights Reserved. An experiment to investigate the effect of pseudo-shock wave (PSW) on turbulent diffusion of a transverse jet in a Mach 2.0 supersonic crossflow was conducted. The vertical jet from a 2.5 mm-diameter orifice was injected into pseudo-shock wave and jetto-crossflow momentum flux ratio was 2.2. To measure turbulent diffusion flux, stereoscopic particle image velocimetry (SPIV) and acetone planar laser-induced fluorescence (PLIF) system were combined and velocity and concentration fields were simultaneously measured. Measurement plane was a cross section at 10 mm downstream from the injection port. The position of PSW was controlled by a flow plug at the duct exit driven by a stepping motor. The front of PSW was set at 30 mm upstream from the orifice. Without PSW, turbulent diffusion flux (TDF) of the injectant was extended upward and the shape of injectant plume was deformed by a counter-rotating vortex pair (CVP) which was formed behind the injected gas. Under PSW, the CVP made horseshoe-shape concentration distribution. TDF directed from spur of concentration to both free stream side and lee side of the jet. Most of no-PSW condition and outward of under-PSW TDF was concentration-fluctuation-dominant, only inward TDF under PSW emerged as turbulent-dominant. The effect of PSW that enhances diffusion of injected gas was confirmed.

DOI： 10.2514/6.2016-0662

超音速壁面噴射流れ場へ上流擾乱が及ぼす影響査読

浦本翔平, 河内俊憲, 升谷五郎

日本航空宇宙学会論文集 64 ( 4 ) 244 - 252 2016年

Focusing-schlieren visualization in a dual-mode scramjet 査読

Toshinori Kouchi, Christopher P. Goyne, Robert D. Rockwell, James C. McDaniel

Experiments in Fluids 56 ( 12 ) 2015年12月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Springer Science and Business Media LLC

DOI： 10.1007/s00348-015-2081-9

その他リンク： http://link.springer.com/article/10.1007/s00348-015-2081-9/fulltext.html

高速断層シュリーレンによる二次元翼バフェットの可視化査読

山口真伍, 河内俊憲, 小池俊輔, 中島努, 佐藤衛, 神田宏, 柳瀬眞一郎

日本航空宇宙学会論文集 63 ( 4 ) 166 - 174 2015年

担当区分：責任著者記述言語：日本語出版者・発行元：日本航空宇宙学会

We visualized two-dimensional wing buffet using fast-framing focusing schlieren method. A supercritical airfoil of NASA SC(2)-0518 was used in this study. Mach number of the freestream was 0.7, and Reynolds number based on the wing code (c) was 5×106. Angle of attack without corrections (α) was changed from 4° to 6°. The present focusing schlieren system had ±18mm depth of field, which was narrow than spanwise region where the two-dimensionality of the flow field was maintained. 8,345 successive images were captured by high speed CMOS camera with 7,000 frames per second with 20μs exposure time. The present imaging system well captured the shock wave motion on the airfoil. At α = 4°, the shock wave was positioned at x/c∼0.45. The shock wave was slightly fluctuated with a frequency of 585.5Hz. Above α = 5°, the wing buffet occurred. The buffet frequency increased as increasing α. The focusing schlieren movies revealed that the shock wave was bifurcated on the wing surface, as the shock traveling upstream. The boundary layer largely separated from the leading oblique foot of the bifurcated shock wave, whereas, the bifurcated shock wave changed into a normal shock and the flow separation disappeared, as the shock traveling downstream. For both cases, many pressure waves propagated from the downstream of the shock wave to the upstream. These waves merged with the shock wave, and seem to drive the shock oscillation.

DOI： 10.2322/jjsass.63.166

その他リンク： http://ousar.lib.okayama-u.ac.jp/56129

枚葉式半導体洗浄装置内に形成される渦の周期構造査読

河内俊憲, 福田修也, 中野裕介, 清水義也, 永田靖典, 柳瀬眞一郎

日本機械学会論文集 81 ( 829 ) 15 - 00273 2015年

Collaborative Experimental and Computational Study of a Dual-Mode Scramjet Combustor 査読

Rockwell, Robert D., Jr., Goyne, Christopher R., Rice, Brian E., Kouchi, Toshinori, McDaniel, James C., Edwards, Jack R.

Journal of Propulsion and Power 30 ( 3 ) 530 - 538 2014年5月

Combined Stereo-PIV and PLIF Measurements of Transverse Injection in Mach 2 Supersonic Flow 査読

Toshinori KOUCHI, Yoshinori OKA, Goro MASUYA, Shinichiro YANASE

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN 12 ( APISAT-2013 ) a85 - a92 2014年

枚葉式半導体洗浄機モデル内渦構造のPIV計測査読

清水義也, 柳瀬眞一郎, 河内俊憲, 森洋平, 福田修也

日本機械学会論文集 80 ( 815 ) FE0197 - FE0197 2014年

Characteristics of Hydrogen Jets in Supersonic Crossflow: Large-Eddy Simulation Study 査読

Watanabe, Junya, Kouchi, Toshinori, Takita, Kenichi, Masuya, Goro

Journal of Propulsion and Power 29 ( 3 ) 661 - 674 2013年5月

Supersonic Combustion Using a Stinger-Shaped Fuel Injector 査読

Kouchi, Toshinori, Masuya, Goro, Hirano, Kohshi, Matsuo, Akiko, Tomioka, Sadatake

Journal of Propulsion and Power 29 ( 3 ) 639 - 647 2013年5月

Large-Eddy Simulation of Jet in Supersonic Crossflow with Different Injectant Species 査読

Junya Watanabe, Toshinori Kouchi, Kenichi Takita, Goro Masuya

AIAA JOURNAL 50 ( 12 ) 2765 - 2778 2012年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER INST AERONAUTICS ASTRONAUTICS

The effects of injectant species on the turbulent structure and mixing state of jets in supersonic crossflow were investigated using a large-eddy simulation. Hydrogen, helium, nitrogen, and ethylene were transversely injected into a Mach 1.9 airflow at a constant jet-to-crossflow momentum flux ratio. The time-averaged distribution of jet concentration was roughly the same for all the injectant species, but the large-scale structure of scalar fluctuation differed significantly. The probability density functions of injectant mass fraction revealed that the turbulent behavior of nitrogen and ethylene jets was highly intermittent. The velocity field was considerably different between the injectants, owing to the different injection velocities. The hydrogen and helium jets had a much higher velocity difference between jet and crossflow in the near field; thus, the observed turbulent intensities for these two injectants were much higher than those for nitrogen and ethylene. In addition, the spectral analysis of velocity fluctuations in the windward mixing layer showed that the scale of energetic eddies was larger in the hydrogen and helium jets than in the nitrogen and ethylene jets. These characteristics resulted in better mixing in the hydrogen jet than in the ethylene jet for the studied injection conditions.

DOI： 10.2514/1.J051550

Flowfield characteristics of a transverse jet into supersonic flow with pseudo-shock wave 査読

H. Yamauchi, B. Choi, K. Takae, T. Kouchi, G. Masuya

Shock Waves 22 ( 6 ) 533 - 545 2012年11月

記述言語：英語掲載種別：研究論文（学術雑誌）

We performed an experimental investigation of the flowfield of a transverse jet into supersonic flow with a pseudo-shock wave (PSW). In this study, we injected compressed air as the injectant, simulating hydrocarbon fuel. A back pressure control valve generated PSW into Mach 2. 5 supersonic flow and controlled its position. The positions of PSW were set at nondimensional distance from the injector by the duct height (x/H) of -1. 0, -2. 5, and -4. 0. Particle image velocimetry (PIV) gave us the velocity of the flowfield. Mie scattering of oil mist only with the jet was used to measure the spread of the injectant. Furthermore, gas sampling measurements at the exit of the test section were carried out to determine the injectant mole fraction distributions. Gas sampling data qualitatively matched the intensity of Mie scattering. PIV measurements indicated that far-upstream PSW decelerated the flow speed of the main stream and developed the boundary layer on the wall of the test section. The flow speed deceleration at the corner of the test section was remarkable. The PSW produced nonuniformity in the main stream and reduced the momentum flux of the main stream in front of the injector. The blowing ratio, defined as the square root of the momentum flux ratio, of the jet and the main stream considering the effect of the boundary layer thickness was shown to be a useful parameter to explain the jet behavior. © 2012 Springer-Verlag.

DOI： 10.1007/s00193-012-0384-9

Turbulent Characteristics for Jet Injected into Supersonic Flow with Pseudo Shock Wave 査読

Byugil Choi, Koichi Takae, Toshinori Kouchi, Goro Masuya

JOURNAL OF PROPULSION AND POWER 28 ( 5 ) 971 - 981 2012年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER INST AERONAUTICS ASTRONAUTICS

The mean and turbulent velocity field of a transverse jet in a supersonic flow with a pseudo shock wave by stereoscopic particle image velocimetry was measured. Both the mainstream and the injectant were unheated air. The pseudo shock wave was generated and controlled by means of a flow plug driven by a stepping motor. To study the influence of the generation and development of the pseudo shock wave, measurements are taken for four different cases of the pseudo shock wave location, including one without a pseudo shock wave. Sequences of up to 750 image pairs for each measurement plane were acquired. From these data, the mean and turbulent characteristics of the flowfield were examined, such as mean velocity and vorticity, turbulence intensities, Reynolds stresses, and turbulence kinetic energy. The mean velocity and vorticity indicate that the pseudo shock wave gradually lowered the flow speed of the mainstream and increased the size of the counter-rotating vortex pair. The pseudo shock wave strongly disturbed the flowfield, inducing complicated three-dimensional distortions. The pseudo shock wave disturbed the flowfields near the walls, and the turbulence kinetic energy in this area was kept at a high level over long streamwise distances. The streamwise fluctuation intensity was about 4 times stronger than that of the vertical and lateral components, and the streamwise velocity components fluctuated even more greatly than the cross-sectional velocity components. The transverse injection moderately affected not only turbulence around the jet, but also the turbulent characteristics caused by the pseudo shock wave. The injection not only produced turbulence around the jet, but also suppressed the velocity fluctuation caused by the pseudo shock wave.

DOI： 10.2514/1.B34371

Flowfield Characteristics of a Hypermixer Interacting with Transverse Injection in Supersonic Flow 査読

Chae-Hyoung Kim, In-Seuck Jeung, Byungil Choi, Toshinori Kouchi, Goro Masuya

AIAA JOURNAL 50 ( 8 ) 1742 - 1753 2012年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER INST AERONAUTICS ASTRONAUTICS

Nonreacting experiments were conducted at Mach 2 to understand the relationship between a wall-mounted alternating-ramp-wedge-type hypermixer and transverse injection compared with a step mixer. Experimental techniques such as schlieren visualization and stereoscopic particle image velocimetry were employed to study the three-dimensional flowfield with vortex structures induced by the interaction between the mixer and transverse injection. Without injection, the hypermixer creates a region that contains vortical motions. When a transverse jet is injected in the vortical region, flow parameters on mixing performance, such as the penetration height, vorticity, and turbulent stress, are improved. Three turbulent-stress components show relatively distinct distributions, and strong turbulent stresses are observed at the upper side of the jet plume. Turbulent-stress distributions are significantly associated with strain rate, which peaks along the sonic line of the jet plume.

DOI： 10.2514/1.J051588

Mechanism and Control of Combustion-Mode Transition in a Scramjet Engine 査読

Kouchi, Toshinori, Masuya, Goro, Mitani, Tohru, Tomioka, Sadatake

Journal of Propulsion and Power 28 ( 1 ) 106 - 112 2012年1月

Quantification of convection velocity and dominant scale of large-scale structures by high-speed schlieren imaging

Toshinori Kouchi, Goro Masuya

48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 2012 AIAA 2012-4148 2012年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：American Institute of Aeronautics and Astronautics

We proposed a new method to evaluate simultaneously both convective velocity and scale of dominant turbulent structures captured in a high speed framing schlieren movie. We took 90 time-series schlieren images of a transverse jet into a Mach 2 supersonic flow with 1 MHz sampling. We focused on periodical image gradations due to the turbulent structures within the jet and boundary layer. We remapped the image intensities on the structures along their trajectory as a time-space map. The time-space map showed swept stripe patterns. The presence of the stripe patterns indicates stable structures were periodically generated and convected downstream. Slope of the stripes corresponds to the convective velocities of the structures. Cycles in the space- and time-directions of the stripes correspond to the scale and formation cycle of the dominant structure. Two-dimensional Fourier transform efficiently extracted the dominant ones from the time-space map. We demonstrated this newlyproposed method using two-dimensional Fourier transform accurately evaluated the convective velocity and scale of the dominant turbulent structures within the jet and boundary layer. © 2012 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

DOI： 10.2514/6.2012-4148

Focusing-schlieren visualization in direct-connect dual-mode scramjet

Toshinori Kouchi, Christopher P. Goyne, Robert D. Rockwell, Roger Reynolds, Roland Krauss, James C. McDaniel

18th AIAA/3AF International Space Planes and Hypersonic Systems and Technologies Conference 2012 2012年

掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：American Institute of Aeronautics and Astronautics

Schlieren imaging has high sensitivity for density gradient in a flow field, and easily captures not only shock and expansion waves but also turbulent structures in the flow field. The conventional schlieren imaging, however, cannot capture clearly them in directconnect supersonic combustor tests with long duration, because the severe temperature condition in the combustor locally changes the refractive index of the window glasses for optical access. The conventional schlieren technique is essentially sensitive to the entire region of the light path including the glasses. On the other hand, focusing-schlieren technique has narrow depth of focus. Therefore, the imaging is expected to avoid the thermal distortion of the glasses. In this work, we applied focusing-schlieren imaging to the supersonic combustion tests, and tried to clearly capture the flow features inside a dualmode scramjet. The present system had about ± 5 mm depth of focus, and successfully visualized the flow field in the combustor, though the system sensitivity declined with the tunnel heating up. Combustion drastically changed the flow field inside the combustor, and induced volumetric expansion of fuel jet, resulting in pressure rise. Combustiongenerated pressure rise pushed up the shock train up to the trilling edge of the ramp fuel injector. The system recorded two image pairs by using PIV system. These image pairs yielded the convection velocity of turbulent structures in the combustor. © 2012 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

DOI： 10.2514/6.2012-5834

Large-eddy /reynolds-averaged navier-stokes simulations of a dual-mode scramjet combustor

Jesse A. Fulton, Jack R. Edwards, Hassan A. Hassan, Robert Rockwell, Christopher Goyne, Jim McDaniel, Chad Smith, Andrew Cutler, Craig Johansen, Paul M. Danehy, Toshinori Kouchi

50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition 2012年

掲載種別：研究論文（国際会議プロシーディングス）

Numerical simulations of reacting and non-reacting flows within a scramjet combustor configuration experimentally mapped at the University of Virginia's Scramjet Combustion Facility (operating with Configuration "A") are described in this paper. Reynolds-Averaged Navier-Stokes (RANS) and hybrid Large Eddy Simulation /Reynolds-Averaged Navier-Stokes (LES /RANS) methods are utilized, with the intent of comparing essentially 'blind' predictions with results from non-intrusive flow-field measurement methods including coherent anti-Stokes Raman spectroscopy (CARS), hydroxyl radical planar laser-induced fluorescence (OH-PLIF), stereoscopic particle image velocimetry (SPIV), wavelength modulation spectroscopy (WMS), and focusing Schlieren. NC State's REACTMB solver was used both for RANS and LES /RANS, along with a 9-species, 19-reaction H2-air kinetics mechanism by Jachimowski. Inviscid fluxes were evaluated using Edwards' LDFSS flux-splitting scheme, and the Menter BSL turbulence model was utilized in both full-domain RANS simulations and as the unsteady RANS portion of the LES /RANS closure. Simulations were executed and compared with experiment at two equivalence ratios, pdbl= 0.17 and pdbl= 0.34. Results show that the pdbl = 0.17 flame is hotter near the injector while the pdbl = 0.34 flame is displaced further downstream in the combustor, though it is still anchored to the injector. Reactant mixing was predicted to be much better at the lower equivalence ratio. The LES /RANS model appears to predict lower overall heat release compared to RANS (at least for pdbl = 0.17), and its capability to capture the direct effects of larger turbulent eddies leads to much better predictions of reactant mixing and combustion in the flame stabilization region downstream of the fuel injector. Numerical results from the LES/RANS model also show very good agreement with OH-PLIF and SPIV measurements. An un-damped long-wave oscillation of the pre-combustion shock train, which caused convergence problems in some RANS simulations, was also captured in LES /RANS simulations, which were able to accommodate its effects accurately. Copyright © 2012 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

Effect of vent mixer to mixing characteristics in supersonic flow

Chae Hyoung Kim, In Seuck Jeung, Byungil Choi, Toshinori Kouchi, Goro Masuya

28th Congress of the International Council of the Aeronautical Sciences 2012, ICAS 2012 4 2864 - 2872 2012年

掲載種別：研究論文（国際会議プロシーディングス）

A Mach 2 hydrogen - air supersonic combustor model with no diffuser was designed and operated in atmospheric inflow condition. A new supersonic mixer, which was vent slot mixer (VSM), was developed and fabricated to use as the device of the fuel-air mixing. At low enthalpy inflow condition, a plasma jet torch was used as the igniter and the flame-holder. An isolator was located between the nozzle and the combustor. In supersonic combustion, the VSM had an effect to increase the mixing efficiency compared with the step mixer. While the combustion pressure was increased, the combustion mode was changed from unstable supersonic combustion to dual-mode transition. When the unstable flow of shock train affected the combustor inlet, the VSM was showed that the combustion stability was slightly sustained when compared with the case ofthe step mixer.

Large-eddy simulation of pseudo-shock wave in a square duct

S. Lee, J. Watanabe, T. Kouchi, K. Takita, G. Masuya

18th AIAA/3AF International Space Planes and Hypersonic Systems and Technologies Conference 2012 2012年

掲載種別：研究論文（国際会議プロシーディングス）

Large-eddy simulation (LES) of Pseudo-Shock Wave (PSW) in a square duct was perfomed to study the three-dimensional turbulent structure. A flow with the PSW in the square section duct produced by the high back pressure was reproduced using LES. The inflow Mach number was 2.5 and the inflow boundary layer of 4.2mm thick. The incoming boundary layer for a square duct was established using the multi rescaling method. The Mach number distribution, schlieren image, wall pressure, and velocity data obtained from the LES were compared with the past experimental data. The shock train structure observed in the experiment was well reproduced by the LES. The averaged wall pressure and streamwise velocity distributions agreed well between the LES and the experiments. Also, the distributions of intensity and spatial correlation of velocity fluctuation reasonably agreed between the LES and the experiment, although some differences were observed in the velocity fluctuation intensity distribution at the position of front shock wave. © 2012 by the American Institute of Aeronautics and Astronautics, Inc.

Velocity field in secondary combustor of ejector-jet

Kiyoshi Nojima, Toshinori Kouchi, Goro Masuya, Sadatake Tomioka

18th AIAA/3AF International Space Planes and Hypersonic Systems and Technologies Conference 2012 ( 2012-5838 ) 2012年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：American Institute of Aeronautics and Astronautics

Three-component velocity distributions in a rocket-ramjet combined cycle engine model operating under a sea-level static condition were measured with a stereoscopic particle image velocimetry. The engine model had two rocket nozzles on top wall side of a flow-path and fuel injectors for the secondary combustion. The rocket exhaust was simulated by the cold compressed air injected at operation condition of 2.4 MPa in chamber pressure. The secondary fuel was simulated by the helium gas. The pressure rise due to combustion was simulated by contracting the exit area of flow path by using a flow plug. The separation region appeared in the cowl side in the ensemble-averaged velocity distribution in the case of combustion simulation. The flow around the separation region was strongly disturbed. © 2012 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

DOI： 10.2514/6.2012-5838

Turbulent Structure of Supersonic Flowfield 査読

Shohei Uramoto, Toshinori Kouchi, Goro Masuya

Journal of Fluid Science and Technology 7 ( 2 ) 231 - 241 2012年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：The Japan Society of Mechanical Engineers

We investigated a supersonic flowfield with transverse injection of air or helium by stereoscopic particle image velocimetry and calculated single-time two-point spatial correlations of velocity fluctuations. For both injection gases, the bow shock wave formed by the injection and its reflection from the upper wall could be seen in the mean velocity distribution. In the velocity fluctuation intensity distribution, we observed vibrating counter-rotating vortex pair and the Reynolds stress was formed along the track of the maximum mean velocity gradient. Correlations showed the scale structure of turbulence and the shapes of the correlation region changed with the selected velocity component. Differences were observed between the results obtained for the two injectant species.

DOI： 10.1299/jfst.7.231

Quasi-one dimensional modeling on vitiation effects for a dual-mode combustor

Junji Noda, Masaki Ohkoshi, Toshinori Kouchi, Goro Masuya, Sadatake Tomioka, Robert D. Rockwell, Christopher P. Goyne

18th AIAA/3AF International Space Planes and Hypersonic Systems and Technologies Conference 2012 ( 2012-5862 ) 2012年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：American Institute of Aeronautics and Astronautics

A three-flow-tube, quasi-one dimentional calculation was carried out to estimate modetransition fuel equivalence ratios under clean and vitiated inflow conditions. A simple flame holding model was used in the calculation. In cases of vitiated inflows, both total temperature and total enthalpy matched conditions to that of clean air were tested. Calculated wall pressure distributions were well matched to those of experimental values, qualitatively. Additionally, the ratio of mode-transition equivalence ratio of clean inflow divided by that of vitiated inflow was well matched to that of experimental value. Matched total enthalpy was effective to eliminate the inflow vitiation effects on mode-transition equivalence ratios in a case that thermal choking was attained at constant area exit. However, in a case that thermal choking was attained in the diverging region, matched total enthalpy was not effective. © 2012 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

DOI： 10.2514/6.2012-5862

Characteristic Study on Effect of the Vent Mixer to Supersonic Fuel-Air Mixing with Stereoscopic-PIV Method

Kim, Chae-Hyoung, SEUCK, JEUNG IN, Kouchi, Toshinori, Masuya, Goro

2012年

Turbulence Induced by Transverse Injection and Pseudo-Shock Wave in Supersonic Flow

Goro Masuya, Byung-Il Choi, Koichi Takae, Toshinori Kouchi

20th International Symposium on Air Breathing Engines ( ISABE Paper 2011-1525 ) 2011年9月

Numerical Study on the Turbulent Structure of Transverse Jet into Supersonic Flow 査読

Junya Watanabe, Toshinori Kouchi, Kenichi Takita, Goro Masuya

AIAA JOURNAL 49 ( 9 ) 2057 - 2067 2011年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER INST AERONAUT ASTRONAUT

The three-dimensional turbulent structure and mixing state of a transverse air jet injected into a Mach 1.9 supersonic crossflow were investigated using a large-eddy simulation. Both a grid sensitivity study and detailed comparisons with acetone planar laser-induced fluorescence data were conducted. The large-eddy simulation results well reproduced both the distribution of averaged injectant concentration and the large-scale turbulent features in the windward region of the jet plume. Large-scale vortices on the windward side of the jet plume caused large protrusions of injectant and were the main cause of the turbulent diffusion of injectant toward the crossflow in the near field. The windward large-scale vortex structure consisted of a string of hairpinlike vortices meandering along the jet trajectory. The head of these hairpin vortices tilted toward the upstream and upward directions. The instantaneous combustible injectant mass flux was evaluated by assuming the injectant air to be ethylene. A large amount of combustible injectant existed inside the large-scale protrusions induced by the windward large-scale vortex structure. The combustible injectant mass flow rate passing through the cross section bad substantial fluctuations over time, mainly due to the intermittent appearance of the windward large-scale vortices.

DOI： 10.2514/1.J051067

Mixing Characteristics of Secondary Fuel in RBCC Ejector-Jet Mode Operation

Kiyoshi Nojima, Toshinori Kouchi, Goro Masuya, Sadatake Tomioka

28th International Symposium on Space Technology and Science ( ISTS 2011-a-65 ) 2011年6月

Correlation between Hypermixer and Fuel Injection Locations

Chae-hyoung Kim, In-Seuck Jeung, Byungil Choi, Toshinori Kouchi, Goro Masuya

17th AIAA International Space Planes and Hypersonic Systems and Technologies Conference 2011年4月

Effect of fuel injection location on a plasma jet assisted combustion with a backward-facing step 査読

Kim, Chae-Hyoung, Jeung, In-Seuck, Choi, Byungil, Kouchi, Toshinori, Takita, Kenichi, Masuya, Goro

Proceedings of the Combustion Institute 33 ( 2 ) 2375 - 2382 2011年1月

Large-eddy simulations of hydrogen and ethylene injections into a supersonic crossflow

Junya Watanabe, Toshinori Kouchi, Kenichi Takita, Goro Masuya

47th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 2011 ( 2011-5764 ) 2011年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：American Institute of Aeronautics and Astronautics

Turbulent structure and mixing state of hydrogen and ethylene jets transversely injected into Mach 1.9 supersonic crossflow was numerically investigated using large-eddy simulation. The feature of windward large-scale structure was largely different between the hydrogen and ethylene jets. The ethylene jet had a highly intermittent feature with intensive geometric change of jet plume. The hydrogen jet had much larger velocity difference between the jet and the crossflow in the near-field, thus much higher turbulent intensity was obtained than in the ethylene jet. In addition, the scale of energetic eddy of hydrogen jet was larger in the windward mixing layer. These probably result in the better mixing in the hydrogen jet than in the ethylene jet. © 2011 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

DOI： 10.2514/6.2011-5764

Effect of fuel injection locations with a hyper mixer in supersonic combustion

Chae Hyoung Kim, In Seuck Jeung, Byungil Choi, Toshinori Kouchi, Goro Masuya

47th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 2011 ( 2011-5830 ) 2011年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：American Institute of Aeronautics and Astronautics

A reacting-experiment was conducted to understand the relation between a wallmounted alternating-ramp-wedge type hyper mixer and various injection locations in unheated supersonic flow. The hydrogen gas and a plasma jet torch were used as the fuel and the igniter, respectively. The parallel injection method shows the maximum combustion efficiency for the forced ignition. This is because the fuel-air mixture can be ignited in the heat source (plasma jet) and providing the fuel-air mixture to the plasma jet, i.e., the parallel injection, is very effective to enhance the combustion efficiency. In the cold main flow, the combustion region is restrained and affected by the location of the plasma jet. © 2011 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

DOI： 10.2514/6.2011-5830

Flowfield characteristics on a vent slot mixer in supersonic flow 査読

Kim, C., Sung, K., Jeung, I. -S., Choi, B., Kouchi, T., Masuya, G.

Shock Waves 20 ( 6 ) 559 - 569 2010年12月

Effect of a Vent Slot Mixer with a Plasma Jet Torch in Unheated Supersonic Flow

Chae-hyoung Kim, In-seuck Jeung, Byungil Choi, Toshinori Kouchi, Goro Masuya

46th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit 2010年7月

Penetration Characteristics of Pulsed Injection into Supersonic Crossflow

Toshinori Kouchi, Keita Sasaya, Junya Watanabe, Hiroharu Shibayama, Goro Masuya

46th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit 2010年7月

Scalar spatial correlations in a supersonic mixing flowfield 査読

Hidemi Takahashi, Hiroki Oso, Toshinori Kouchi, Goro Masuya, Mitsutomo Hirota

AIAA Journal 48 ( 2 ) 443 - 452 2010年2月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：AMER INST AERONAUT ASTRONAUT

Single-time two-point spatial correlations of injectant concentrations in the supersonic mixing flowfield produced by a sonic transverse injection of air into a Mach 2.0 supersonic airstream were investigated using acetone planar laser-induced fluorescence data. Side-view and end-view contour maps were obtained in several planes to characterize the turbulent structure and three-dimensionality of the mixing flowfield. The correlation maps indicated an organized large-scale structure in the upper region of the jet. The side-view correlation maps revealed that the shape of the large dominating structure was elliptic and that its major axis turned from backward-leaning to forward-leaning as the reference point of correlation moved downstream. The end-view correlation maps showed that the instantaneous jet plume appeared by turns either in the top or in the lower sides of the time-averaged injectant plume in each cross section. Copyright © 2009 by the American Institute of Aeronautics and Astronautics, Inc.

DOI： 10.2514/1.44684

Development of a New Supersonic Mixier for Dual-Mode Scramjet Engine Combustor

Chae-hyoung Kim, In-Seuck Jeung, Byungil Choi, Toshinori Kouchi, Goro Masuya

16th AIAA/DLR/DGLR International Space Planes and Hypersonic Systems and Technologies Conference 2009年10月

Time-Space Trajectory of Unsteady Jet into Supersonic Crossflow Using High-Speed Framing Schlieren Images

Toshinori Kouchi, Takahisa Hoshino, Keita Sasaya, Goro Masuya

16th AIAA/DLR/DGLR International Space Planes and Hypersonic Systems and Technologies Conference 2009年10月

Mechanism of Mixing Enhanced by Pseudo-Shock Wave

Hideki Yamauchi, Byongil Choi, Toshinori Kouchi, Goro Masuya

47th AIAA Aerospace Sciences Meeting including The New Horizons Forum and Aerospace Exposition 2009年1月

Aerodynamic Experiments of Small Scale Combined Cycle Engine in Various Mach Numbers 査読

TANI Kouichiro, KOUCHI Toshinori, KATO Kanenori, SAKURANAKA Noboru, WATANABE Syuuichi

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, SPACE TECHNOLOGY JAPAN 7 ( ists26 ) Pa_59 - Pa_64 2009年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES

A small model aerodynamic tests of the combined cycle engine were carried out to evaluate its performance in subsonic and supersonic conditions. In this regime of the flow speed, the combined cycle engine operates as an ejector-jet or ramjet. The nitrogen gas was exhausted as the substitution for the actual rocket gas. In a subsonic condition, there appeared local pressure rise at the kink point of the ramp, increasing the pressure drag. Both wall pressure and the pitot pressure distribution at the exit of the model suggested that the flow structure is "two-layered" ; one is subsonic induced air flow, and the other is the supersonic rocket exhaust. A slit was carved on the topwall inside the isolator section, expecting a better suction performance in the ejector-jet mode. The modification actually had an effect to enhance the lower limit of the rocket pressure at which the choking of the induced air is achieved.

DOI： 10.2322/tstj.7.pa_59

Supersonic combustion with supersonic injection through diamond-shaped orifices 査読

S. Tomioka, T. Kohchi, R. Masumoto, M. Izumikawa, A. Matsuo

45th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 27 ( 6 ) 1196 - 1203 2009年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：American Institute of Aeronautics and Astronautics

Supersonic injections through diamond-shaped injectors were applied to a supersonic combustor with a diverging section, with a Mach 2.4 incoming vitiated airflow at a total temperature of 2000 K, and combustion characteristics were experimentally investigated and compared to those with sonic injection through circular injectors. Without any flame-holding devices installed, scramjet-mode combustion was attained in wide range of fuel flow rate, in which the supersonic injections resulted in a higher pressure-rise in far-field than the sonic injections. Regardless of the injection scheme (i.e, orifice shape, orifice number, and injection conditions), transition to dual-mode combustion enhanced the thrust production, and the supersonic injection through the diamond-shaped orifice had lesser ability to cause the transition than the sonic injection through the circular orifice. The ability was enhanced by installation of a recess and introduction of recess fueling, and resulting combustor performance was slightly better than that with the sonic injection, in the case with single orifice. Both the number of the orifice and the injection pressure (by changing the total orifice throat area) were varied for the supersonic injection through the diamond-shaped orifice for fixed fuel flow rates, and the change in combustion characteristics were also reported. © 2009 by the American Institute of Aeronautics and Astronautics, Inc.

DOI： 10.2514/1.B34164

Performance of a scramjet engine model in Mach 6 flight condition 査読

S. Ueda, T. Kouchi, M. Takegoshi, S. Tomioka, K. Tani

Shock Waves 1129 - 1134 2009年

Design and Experimental Verification of Two Dimensional Asymmetric Supersonic Nozzle 査読

김채형, Masuya, Goro, 성근민, 최병일, Kouchi, Toshinori

Journal of the Korean Society for Aeronautical and Space Sciences 37 ( 9 ) 2009年

Combustion Performance of Supersonic Combustor with Stinger-Shaped Fuel Injector

Toshinori Kouchi, Kohshi Hirano, Kan Kobayashi, Sadatake Tomioka, Muneo Izumikawa, Akiko Matsuo

44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit 2008年7月

Matched pressure injections into a supersonic crossflow through diamond-shaped orifices 査読

Tomioka, Sadatake, Izumikawa, Muneo, Kouchi, Toshinori, Masuya, Goro, Hirano, Kohshi, Matsuo, Akiko

Journal of Propulsion and Power 24 ( 3 ) 471 - 478 2008年5月

複合エンジンの静止大気中における吸い込み性能（第2報：エジェクタ二層流解析と吸い込み性能改善）査読

河内俊憲, 富岡定毅, 苅田丈士

日本航空宇宙学会論文集 56 ( 651 ) 163 - 168 2008年

複合エンジンの静止大気中における吸い込み性能（第1報数：値計算による吸い込み性能予測）査読

河内俊憲, 富岡定毅, 苅田丈士

日本航空宇宙学会論文集 56 ( 650 ) 110 - 115 2008年

New Injector Geometry for Penetration Enhancement of Perpendicular Jet into Supersonic Flow

Kohshi Hirano, Akiko Matsuo, Toshinori Kouchi, Muneo Izumikawa, Sadatake Tomioka

43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit 2007年7月

Pulsed Transverse Injection Applied to a Supersonic Flow

Toshinori Kouchi, Noboru Sakuranaka, Muneo Izumikawa, Sadatake Tomioka

43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit 2007年7月

エンジン風洞における超音速流の閉塞査読

三谷徹, 宮島博, 谷香一郎, 河内俊憲, 櫻中登, 渡邊修一

日本航空宇宙学会論文集 55 ( 636 ) 43 - 50 2007年

Performance of a RBCC Combustor Operating in Ramjet Mode

Toshinori Kouchi, Kan Kobayashi, Kenji Kudo, Atsuo Murakami, Kanenori Kato, Tomioka Sadatake

42nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit 2006年7月

Evaluation of heat-flux on scramjet engine wall in Mach 6 flight condition

Shuichi Ueda, Masao Takegoshi, Toshinori Kouchi, Fumiei Ono, Toshihito Saito, Muneo Izumikawa

AIAA 57th International Astronautical Congress, IAC 2006 9 6344 - 6353 2006年

掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：American Institute of Aeronautics and Astronautics

Space transportation system uses the liquid hydrogen of the fuel as a coolant of the engine. Therefore, it is necessary to predict the heat flux to the engine wall in high accuracy for efficient cooling with a minimum coolant. However, the prediction of the heat flux to the scramjet engine combustor walls, is quite difficult due to complex interaction of flow and combustion. In this study, a sidewall-compression-type scramjet engine was tested under Mach 6 flight conditions using Ramjet Engine Test Facility. The heat flux was measured using water-cooled heat-flux meters installed on the sidewall within the combustor sections. The experimental results were compared with CFD analysis of the whole engine to predict heat flux distribution on the engine wall. The numerical results of wall pressure distribution showed good agreement with the experimental data. However, the experimental results of heat flux were extremely higher than the numerical results due to the radiation heating which was not considered in the CFD analysis. Based on the results, the average heat flux of the sub-scale scramjet engine with 300 K isothermal walls was 1 MW/m2 in the stoichiometric fuel rate at Mach 6 flight conditions.

DOI： 10.2514/6.iac-06-c4.5.04

Performance Comparison of Combined Fuel Injection Methods in a Staged-Combustion Scramjet Engine 査読

Ueda, S, Tomioka, S, Kouchi, T, Kobayashi, K, Kudo, K, Kato, K

Proceedings of the 25th International Symposium on Space Technology and Science 121 - 126 2006年

Transition of Combustion Modes in a Scramjet Engine 査読

Kouchi, T, Mitani, T, Tomioka, S, Ueda, S

Proceedings of the 25th International Symposium on Space Technology and Science 107 - 114 2006年

Flame structures and combustion efficiency computed for a Mach 6 scramjet engine 査読

Mitani, T, Kouchi, T

Combustion and Flame 142 ( 3 ) 187 - 196 2005年8月

Numerical simulations in scramjet combustion with boundary-layer bleeding 査読

Kouchi, T, Mitani, T, Masuya, G

Journal of Propulsion and Power 21 ( 4 ) 642 - 649 2005年7月

Problems of Numerical Diffusion Found in Scramjets

Toshinori Kouchi, Tohru Mitani, Goro Masuya

AIAA/CIRA 13th International Space Planes and Hypersonics Systems and Technologies Conference 2005年5月

Heat Flux Prediction for Scramjet Engines, - Accuracy of Reynolds Analogy on Scramjet Internal Walls 査読

Kouchi, T, Mitani, T, Hiraiwa, T, Kodera, M, Masuya, G

Proceedings of the 24th International Symposium on Space Technology and Science 20 - 26 2004年

RJTF試験におけるスクラムジェット性能達成度査読

三谷徹, 富岡定毅, 苅田丈士, 谷香一郎, 鎮西信夫, 河内俊憲

日本航空宇宙学会論文集 52 ( 600 ) 1 - 9 2004年

Numerical Experiments of Scramjet Combustion with Boundary-Layer Bleeding

Toshinori Kouchi, Tohru Mitani, Masatoshi Kodera, Goro Masuya

12th AIAA International Space Planes and Hypersonic Systems and Technologies 2003年12月

抗力測定によるスクラムジェットの推力性能見積り査読

河内俊憲, 三谷徹, 平岩徹夫, 富岡定毅, 升谷五郎

日本航空宇宙学会論文集 51 ( 595 ) 403 - 411 2003年

Effects of Reynolds Number on Scramjet Inlet Performance 査読

Kouchi, T, Mitani, T, Kodera, M, Masuya, G

Proceedings of the 23rd International Symposium on Space Technology and Science 21 2412 - 2417 2002年

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