Language：English   Publishing type：Research paper (scientific journal)   Publisher：International Journal of Aeronautical and Space Sciences  

One of the problems relating to frost formation in the field of aviation is the effects of Cold Soaked Frost. It is hazardous problem for which various solutions are the responsibility of several aviation administrations. Owing to the lack of computational research on frost formation such as on a wing surface, an advanced model for predicting frost thickness under a various range of flow conditions was developed and validated in this study. In evaluating the growth rate of the solid layer, the relation between the partial vapor pressure and the saturation pressure was used to determine the supersaturation degree. Frost thickness was assumed on the basis that the mass transfer effects associated with the diffusivity of the vapor are related mainly to the growth rate of crystallization. We performed a favorable regression procedure to find constant values for the correlation of the growth rate. The proposed frost thickness model was validated through the comparison of the simulation results with various experimental data for the case of a flat plate. The results obtained using the proposed model agree satisfactorily with the experimental data.

DOI： 10.1007/s42405-022-00464-5

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Language：English   Publishing type：Research paper (scientific journal)  

The reentry blackout phenomenon, which is the communication cut-off between the re-entry vehicle and ground station, is a crucial problem that needs to be addressed. To improve safety during reentry, a new mitigation method was proposed using the surface catalysis effect.
However, this method has not been investigated extensively by experimental methods. In this study, we experimentally demonstrated the mitigation method using a 1 MW arc-heated wind tunnel and numerically clarified the mitigation mechanism. As a demonstration experiment, communication tests were conducted to compare the two cases. In the first case, a ceramic surface was used as a low catalytic wall, whereas in the second case, a copper surface was used
as a high catalytic wall in the arc-heated wind tunnel. The experimental results indicated that the blackout occurred when alumina was used as the low catalytic wall. On the other hand, for the high catalytic wall using copper, blackout was avoided. The tests were reproduced in the wind tunnel using a numerical simulation technique. From the simulation results, the mitigation mechanism suggested that: (a) the number of nitrogen and oxygen atoms decreased due to catalysis; (b) forward reactions of electron impact ionization were suppressed due to the decrease in the number of atoms; and (c) the suppression of reactions decreased the number of electrons, thereby mitigating the reentry blackout. In addition, the numerical simulations performed on the reentry plasma around the re-entry capsule suggested that the mitigation mechanisms between the arc-heated wind flow and reentry plasma were similar despite the different airflow conditions.

DOI： 10.1088/1361-6463/abe746

Other Link： https://iopscience.iop.org/article/10.1088/1361-6463/abe746

Language：English   Publishing type：Research paper (international conference proceedings)  

A numerical computation of the physical properties for the humid vapor sublimated on a commercial wing surface at constant atmospheric conditions was performed and presented in this paper. The frost formation model was based on the gradient of the vapor concentration with the consideration of the heat and mass transfer effects. To express the solid layer, a sink term in the momentum equation was used which is defined as the porous medium. And, to operate the sink term as a trigger in the momentum equation, the volumetric expression was defined during the simulation. The schematic of the frost formation at the upper surface of the wing was assumed that the formation process is similar to the case of the flat plate. The process of the sublimation was performed with the model based on the mass flow rate. In the energy equation, the term of the latent heat and sublimation heat, respectively, was considered as the general theory. The formation case of the wing surface was performed with some boundary conditions where the wing object was exposed to the cold environment. For that, the numerical condition for the computational simulation was mainly based on few reference data provided.

Language：English   Publishing type：Research paper (scientific journal)  

In this study, a three-dimensional simulation of a fish-like body swimming in a channel with non-slip walls was carried out to investigate the effects of kinematics on swimming performance. Self-propelled swimming in an inertial coordinate system was examined by using the direct forcing immersed boundary method. The fish body consisted of several rigid bodies, and behaved analogously to a multi-segment robotic fish. The computational program was first validated by simulating flow around a circular cylinder at Re=100 and 1000 as well as a settling particle in fluid. The results were compared with experimental and numerical results from past research in the area. A virtual parametric study of the tail-beat frequency, phase difference between neighbouring body segments and body amplitude was then conducted. The effect of the lateral distance between the model and walls on swimming performance is also discussed. The results for the velocity and vorticity fields around the model provided evidence for the mechanism of thrust generation and highlighted the effects of kinematics on swimming performance.

DOI： 10.1080/19942060.2018.1453381

Language：English   Publishing type：Research paper (scientific journal)  

A numerical simulation model of plasma flows and electromagnetic waves around a vehicle was developed to predict a radio frequency blackout. Plasma flows in the shock layer and the wake region were calculated using a computational fluid dynamics technique with a three-dimensional model. A finite-catalytic wall condition known to affect plasma properties, such as the number density of electrons, was considered for accurate prediction. A parametric study was performed to investigate the effect of uncertainty in the chemical reaction rate model on evaluating a radio frequency blackout. The behavior of electromagnetic waves in plasma was investigated using a frequency-dependent finite-difference time-domain method. Numerical simulations of reentry blackout were performed for the Atmospheric Reentry Demonstrator mission at various altitudes. The plasma flows and the complex movement of electromagnetic waves around the Atmospheric Reentry Demonstrator vehicle were clarified. The predicted signal loss profile was then directly compared with the experimental flight data to validate the present models. The numerical results generally reproduced the trends over altitudes of the measured data. It is suggested that the present simulation model can be used to investigate the radio frequency blackout and signal loss of electromagnetic waves in the communication of a reentry vehicle. It was confirmed that high associative ionization reaction rates contribute to reducing the electron density in the wake region and radio frequency blackout. It is suggested that the accuracy of predicting the signal loss improved when considering the uncertainty in the chemical reaction model for associative ionizations.

DOI： 10.1063/1.5010713

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

Numerical simulations of plasma flows and electromagnetic waves around a reentry vehicle were performed to estimate the radio-frequency blackout. The plasma flows in the shock layer and wake region were calculated using computational fluid dynamics technique. The simulation of electromagnetic waves around a reentry vehicle was conducted using a frequency-dependent finite-difference time-domain method with the plasma properties obtained by computational fluid dynamics. The numerical simulations were performed for the atmospheric reentry demonstrator at various altitudes based on the reentry orbit data. Three cases of the numerical simulations, i.e., an axisymmetric model, a three-dimensional model with non-catalytic wall and finite-catalytic wall, were performed for evaluating the effects of angle of attack and catalytic wall on the radio-frequency blackout. The formations for the number density of electrons that is an important parameter in evaluating the radio-frequency blackout were greatly changed by these three cases. The simulation model was validated based on the signal loss history of the experimental flight data. The simulation results using a three-dimensional model with finite-catalytic wall showed better agreement with the measured results compared to other two cases.

DOI： 10.2514/6.2017-3308

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

A three-dimensional numerical simulation model that considers the effect of the angle of at-tack was developed to evaluate plasma flows around reentry vehicles. In this simulation model, thermochemical nonequilibrium of flowfields is considered by using a four-temperature model for high-accuracy simulations. Numerical simulations were performed for the orbital reentry experiment of the Japan Aerospace Exploration Agency, and the results were compared with experimental data to validate the simulation model. A comparison of measured and predicted results showed good agreement. Moreover, to evaluate the effect of the angle of attack, we performed numerical simulations around the Atmospheric Reentry Demonstrator of the European Space Agency by using an axisymmetric model and a three-dimensional model. Although there were no differences in the flowfields in the shock layer between the results of the axisymmetric and the three-dimensional models, the formation of the electron number density, which is an important parameter in evaluating radio-frequency blackout, was greatly changed in the wake region when a non-zero angle of attack was considered. Additionally, the number of altitudes at which radio-frequency blackout was predicted in the numerical simulations declined when using the three-dimensional model for considering the angle of attack.

DOI： 10.3938/jkps.68.1295

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Two-dimensional (2D) numerical simulations of thermochemical nonequilibrium inductively coupled plasma (ICP) flows inside a 10-kW inductively coupled plasma wind tunnel (ICPWT) were carried out with nitrogen as the working gas.

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2514/1.T4130

Language：English   Publishing type：Research paper (scientific journal)  

Numerical simulations of 10-kW and 110-kW inductively coupled plasma (ICP) wind tunnels were carried out to study the physical properties of the flow inside the ICP torch and vacuum chamber with air as the working gas. Two-dimensional compressible axisymmetric Navier-Stokes (N-S) equations that took into account 11 species and 49 chemical reactions of air were solved. To reduce computational cost, a heat source model was used to describe the heating phenomenon instead of solving the governing equations of the electromagnetic field. In the vacuum chamber, a four-temperature model was coupled with N-S equations. Numerical results for the 10-kW ICP wind tunnel are presented and discussed in detail as a representative case. It was found that the plasma flow in the vacuum chamber tended to be local thermochemical equilibrium. To study the influence of operating conditions on the flow field, simulations were carried out for different chamber pressures and/or input powers. To validate the numerical methods used here, the computational results for the above two ICP wind tunnels were compared with corresponding experimental data. The computational and experimental results agree well, therefore the flow fields of ICP wind tunnels can be clearly understood.

DOI： 10.1088/1009-0630/16/10/06

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

Turbulent plasma flows in arc heaters, such as Japan Aerospace Exploration Agency’s 750 kW, NASA’s 20 MW, and Kyushu University’s 20 kW facilities, were investigated, and the distributions of the flowfield properties were successfully obtained. The arc discharge in the constrictor section and the expansion processes in the nozzle section played key roles in the formation of an arc-heated flow. Hence, for accurately predicting high-enthalpy flow properties, it was important to correctly model the complex phenomena observed in various-scale facilities. For this purpose, an integrated analysis model to simulate various-scale arc-heated flows with high accuracy was developed. The turbulent flowfield was described using the Reynolds-averaged Navier–Stokes equations with a multitemperature model, which was tightly coupled with electric-field and radiation-field calculations. A sophisticated and low-cost radiation model and a low-Reynolds-number two-equation turbulence model were introduced into the flowfield simulation. To validate the present integrated analysis model, the computed results were compared with the corresponding experimental data for the mass-averaged enthalpy, the translational and rotational temperatures, and the number density of nitrogen obtained through spectroscopic and laser-induced fluorescence techniques. Moreover, the mechanisms of energy input by discharge and energy loss are discussed, along with the distributions of the electronic excitation temperature and heat flux on the constrictor wall derived from the arc column. Although the results indicated that a relatively detailed discharge model is required to describe the arc discharge with relatively high accuracy, the present flowfield model was generally in good agreement with various operating conditions of the facilities.

DOI： 10.2514/1.T3991

Language：English   Publishing type：Research paper (scientific journal)  

Numerical simulation of the flow fields was performed for the mission of Apollo AS-202 to investigate the influence of the laminar-turbulent transition position in the boundary layer around a reentry capsule on the heat flux at the wall. For this purpose, we intentionally varied the laminar-turbulent transition position and the obtained results were compared. According to the simulation result, in the turbulent case, heat flux value is about 1.4 times at maximum compared with the laminar case. It turned out that the transition position had a large influence on the heat flux at the wall, particularly in the forebody region. On the other hand, in the afterbody region, some discrepancies were seen compared with the flight data.

DOI： 10.1016/j.proeng.2013.12.025

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

Numerical simulation of a light-weight ablator in an arc-heated flow was carried out. Thermal response analysis of the ablator was coupled with thermochemical nonequilibrium analysis of an arc jet around the ablator. In the thermal response analysis, the pyrolysis gas flow inside the ablator was calculated in detail by solving the conservation equations. Phenomena such as heat conduction, pyrolysis of resin, surface reactions and recession were also considered in the simulation. Furthermore, in order to evaluate the injection of the ablation gas (pyrolysis gas and carbonaceous gas generated by the surface reactions) from the ablator surface into the outer flow field, a computational fluid dynamics (CFD) code was extended by including further chemical species besides those in the previous study. This also allowed the simulations for wider-range flow conditions such as a nitrogen flow and an air flow. The simulation was conducted for flow conditions of a 20 kW arc-heated nitrogen flow and a 750 kW arc-heated air flow. The results from the former simulation were compared with the experimental data and the computational results using other models. This comparison showed that the effect of the pyrolysis gas flow on the thermal response was significant and thus the detailed analysis considering the multi-dimensional pyrolysis gas flow led to considerable improvement of the predictive performance.

DOI： 10.1615/ComputThermalScien.2012004762

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Numerical simulation of a light-weight ablator in an arc-heated flow was carried out. Thermal response analysis of the ablator was coupled with thermochemical nonequilibrium analysis of an arc jet around the ablator. In the thermal response analysis, the pyrolysis gas flow inside the ablator was calculated in detail by solving the conservation equations. Phenomena such as heat conduction, pyrolysis of resin, surface reactions and recession were also considered in the simulation. Furthermore, in order to evaluate the injection of the ablation gas (pyrolysis gas and carbonaceous gas generated by the surface reactions) from the ablator surface into the outer flow field, a computational fluid dynamics (CFD) code was extended by including further chemical species besides those in the previous study. This also allowed the simulations for wider-range flow conditions such as a nitrogen flow and an air flow. The simulation was conducted for flow conditions of a 20 kW arc-heated nitrogen flow and a 750 kW arc-heated air flow. The results from the former simulation were compared with the experimental data and the computational results using other models. This comparison showed that the effect of the pyrolysis gas flow on the thermal response was significant and thus the detailed analysis considering the multi-dimensional pyrolysis gas flow led to considerable improvement of the predictive performance.

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1088/0022-3727/43/18/185201

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2514/1.13603

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jweia.2005.09.003

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s11630-003-0032-x

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s001930200135

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (bulletin of university, research institution)  

Event date： 2022.11

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2022.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Event date： 2022.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Event date： 2021.12 - 2022.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Event date： 2021.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

The radio-frequency blackout, which is the communication cutoff between a reentry vehicle and ground station during the atmospheric reentry, has been observed for many missions. Aerodynamic heating caused by a strong shock wave in front of the reentry vehicle dissociates and ionizes the gas. This plasma can block the propagation of electromagnetic waves emitted from the antenna on the vehicle. To mitigate the communication blackout, it is significant to reduce the electron number density near the reentry vehicle. We focused on a new mitigation scheme by film cooling approach. Cold gas injected from the vehicle’s surface forms a thin heat-insulating air film layer where electromagnetic waves can propagate because of the low degree of ionization. In this study, we investigated the effects of the air film for the blackout mitigation using a communication test and computational fluid dynamics (CFD) approach for flow field in the large-scale arc-heated wind tunnel. The communication test results and the computed results indicated that gas the air film forms a propagation path of the electromagnetic waves.

Event date： 2021.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

A longitudinal vortex appears in many kinds of flow fields of engineering interest and is known to give large influence on the performance of fluid machinery. Therefore, it is important to study how vortex structures interact with each other. In this study, the interaction of unsteady longitudinal vortices under various conditions was investigated numerically. We considered a wing tip vortex generated on an airfoil, and made it interact with a longitudinal vortex generated from a flat plate with several patterns of unsteady motions. From the computational results, we investigated how the introduced vortex from the flat plate affected the wing tip vortex, and consequently the lift and drag coefficients.

Event date： 2021.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

The radio frequency blackout that occurs during a spacecraft re-entry is a complicated phenomenon that is not well understood, and more detailed studies are thus neccesary. In this paper, a numerical study of flow fields around a test model in an arc-heated wind tunnel was performed. Furthermore, the electromagnetic field simulation using a frequency dependent finite difference time domain (FD2TD) method was also performed to clarify the behavior of radio waves. To discuss the validity and further improvement of the simulation, the model was placed with an inclined angle from the nozzle exit, as well as in a straight line. The obtained results are compared with some experimental data.

Event date： 2021.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Recently, from a viewpoint of CO2 reduction and energy saving, further reduction of fuel consumption for automobiles has become more and more important. For this purpose, reducing the air resistance of a vehicle body is essential because it is much larger than the other road resistances in high-speed driving. Around a vehicle body, various unsteady vortex structures are generated, and their control is known to be important for the aerodynamic performance. In this study, to investigate the vortex structures in more detail, we analyzed simulation results of a flow field around the Ahmed body using Snapshot Proper Orthogonal Decomposition (SPOD) considering frequency characteristics in each mode. Particularly, we adopted two types of flow variables, i.e., velocity and vorticity, in creating the expansion coefficients of POD, and the obtained results were compared to find difference in their features.

Event date： 2021.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Event date： 2021.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Sweeping jet (SWJ) actuator was introduced to an axisymmetric bump model with the aim to control transonic turbulent boundary-layer separation. Three-dimensional unsteady Reynolds-averaged Navier-Stokes (RANS) simulation was used to investigate the flow control performance of SWJ Actuator with different momentum coefficient. Furthermore, we conducted numerical analysis of a steady jet actuator as another flow control device, and then discussed advantage of SWJ Actuator.

Event date： 2021.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

To predict the radio-frequency blackout precisely, an accurate estimation of the electron number density is indispensable. However, its prediction in our numerical analysis system had been considerably overestimated. In this study, we tried to improve the prediction accuracy of the electron number density of a plasma flow in an arc-heated wind tunnel. In particular, we investigated the sensitivity of several simulation factors on the prediction of the electron number density, e.g., chemical-reaction parameters and Joule-heating conditions.

Event date： 2020.12 - 2021.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Recently, from a viewpoint of CO2 reduction and energy saving, further reduction of fuel consumption for automobiles has become more and more important. For this purpose, reducing the air resistance of a vehicle body is essential because it is much larger than the other road resistances in high-speed driving. Around a vehicle body, various unsteady vortex structures are generated, and their control is known to be important for the aerodynamic performance. However, these structures are very complex and thus it is difficult to elucidate their essential features. In this study, to investigate the vortex structures in more detail, we performed flow computations of a channel flow and the obtained results were analyzed using Snapshot Proper Orthogonal Decomposition (SPOD) considering frequency characteristics in each mode.

Event date： 2020.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

The consideration of turbulence is essential for investigating a high Reynolds number flow field, such as that around an aircraft or a automobile. Owing to the development of super computers, computational fluid dynamics (CFD) has become more and more useful for understanding such complex flow phenomena. Although large eddy
simulation (LES) is promising among CFD strategies, its computational cost is still problematic. To reduce the computational cost of LES, the development of a sub-grid scale (SGS) model is indispensable. In this study, a regression of SGS stresses is performed using machine learning (ML). For the present ML, highly-resolved LES data of a plane channel flow are adopted as a teacher dataset, and the results obtained from the regression are carefully investigated by comparison with the target data.

Event date： 2020.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：宇宙科学研究所(相模原市）   Country：Japan  

触媒性再結合反応による通信ブラックアウトの低減化が数値的に実証されている．アーク加熱風洞を用いて低減化を実験的に実証するため，ISAS 1MWアーク加熱風洞において通信実験を実施した.低触媒材料であるセラミックのケースでは通信ブラックアウトが生じたのに対し，高触媒材料である銅のケースでは生じなかった．この結果は触媒効果による通信ブラックアウト低減化実証を示唆するものである．

Event date： 2020.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Reentry blackout during the atmospheric reentry interrupts communication between the reentry vehicle and ground stations. To improve safety during reentry, a mitigation method using the surface catalysis effect was proposed. An experimental test of this method using the arc-heated wind tunnel was performed. However, its mechanism is not clear. In this study, we numerically simulated plasma flows in the ISAS 1MW arc-heated wind tunnel and around the atmospheric reentry demonstrator (ARD). Computed results for the non-catalytic and finite-catalytic wall conditions were compared with each analysis. The results showed that the dominant chemical reaction to reentry blackout was the electron-impact ionization. The mitigation mechanism was clarified as follows: 1) the amount of nitrogen and oxygen atoms decreased because of the catalyst; 2) reverse reactions of the electron impact ionization occurred to increase the number of nitrogen and oxygen atoms due to the decrease in atoms; 3) These reverse reactions consumed electrons and thus the reentry blackout was mitigated. It was found that these mechanisms were in common, despite the different airflow conditions between the arc-heated wind tunnel and atmospheric reentry.

Event date： 2020.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸大学(神戸市)   Country：Japan  

Event date： 2020.3

Language：Japanese  

Venue：神戸大学(神戸市）   Country：Japan  

Event date： 2020.2

Language：English   Presentation type：Oral presentation (general)  

Venue：BORDEAUX (FRANCE)   Country：Japan  

Reentry blackout is one of the most important problems during the atmospheric reentry. In this study, we demonstrated a new mitigation method for the reentry blackout using surface catalysis effects, conducting an experiment using arc-heated wind tunnel. Firstly, for a feasibility study, we carried out plasma flow and electromagnetic waves analyses to reproduce blackout environment for non-catalysis and finite catalysis cases in the JAXA/ISAS 1MW arc-heated flow. In the numerical analysis, the electromagnetic wave was completely blocked due to reentry blackout for the case of the non-catalytic wall. On the other hand, for the case of finite catalytic wall, it was confirmed that the electromagnetic wave propagates. From the experimental results, reentry blackout occurred when using alumina as a low catalytic material. On the other hand, for the case of copper as a high catalytic material, it was found that reentry blackout is avoided.

Event date： 2019.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：北海道大学   Country：Japan  

Event date： 2019.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：北海道大学   Country：Japan  

Event date： 2019.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：北海道大学   Country：Japan  

Event date： 2019.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：北海道大学   Country：Japan  

Event date： 2019.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：北海道大学   Country：Japan  

Event date： 2019.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：北海道大学   Country：Japan  

Event date： 2019.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：横浜国立大学   Country：Japan  

Numerical simulation of plasma flow around a probe in an arc-heated wind tunnel was performed by using flow field simulation. Plasma parameters necessary for electromagnetic wave analysis were obtained. Electromagnetic wave analysis was performed using frequency dependent finite difference time domain (FD2TD) method. Compared with the experimental results, it was found that the analysis result greatly estimates the attenuation of electromagnetic waves. Parametric study on diffusion coefficient of electrons showed that diffusion coefficient of electrons greatly affects communication possibility

Event date： 2018.12

Language：Japanese  

Venue：機械振興会館   Country：Japan  

Event date： 2018.12

Language：Japanese  

Venue：機械振興会館   Country：Japan  

Event date： 2018.12

Language：Japanese  

Venue：機械振興会館   Country：Japan  

Event date： 2018.12

Language：Japanese  

Venue：機械振興会館   Country：Japan  

Event date： 2018.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学伊都キャンパス   Country：Japan  

Event date： 2018.10

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：久留米シティプラザ   Country：Japan  

The radio frequency blackout that occurs when a spacecraft reentry was reproduced in experiments using an arc heated wind tunnel. A ϕ50 probe that is cooled by water and a radio transmitter installed was setting in the arc heated flow, and a radio receiver was setting up outside of tunnel chamber. The blackout was confirmed as the communication stoppage between the transmitter and the receiver. Additionally, Three dimensional flow field around the probe with radio transmitter located in the arc heated wind tunnel was simulated by numerical simulation. The result of numerical simulation agrees with the experimental result that showed radio frequency blackout. Comparing the results of experiments and simulation makes it possible to improve the accuracy of numerical simulation of the radio frequency blackout.

Event date： 2018.6

Language：English  

Venue：Atlanta   Country：United States  

Numerical study on the condensed and frozen vapor on a flat plate was performed to estimate the trends of the freezing of water vapor and its thickness. For the simulation of the phase change of water vapor for the freezing, VOF(Volume of Fluid) method was used. As the freezing area growth, we investigated the flow-velocity variation in the wall-normal direction. Zero-velocity region in the frozen layer was calculated using the Carman-Kozeny equation deriving from the Darcy law in the momentum equation. The phase change rate was assumed to be mainly related the temperature difference between a plate and atmosphere. Basic concept of the freezing phenomenon was combined with the condensation vapor schematics. The calculation for the volumetric generation rate and the freezing rate of water-vapor was controlled by the thermophysical approaches and the enthalpy-porosity method to model the condensation and the freezing, respectively. The numerical simulation was conducted using an open source code, named OpenFOAM®. The obtained results were compared to the corresponding references for the variation of the frozen thickness by the phase change. The comparison of the prediction results with the reference data showed god agreement. Also, positive possibilities of the performance for obtaining better results are expected by using additional complements in further studies.

Event date： 2018.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東北大学   Country：Japan  

Using a three-dimensional model considering an angle of attack and catalytic reaction of surface, numerical simulations of plasma flow and electromagnetic waves around an atmospheric reentry demonstrator (ARD) were performed. The comparison of the distributions of flow-field properties was obtained between the non-catalytic wall and the finite-catalytic wall model. The comparison of the results of two models, it was shown that wall condition has strong influence on the distribution of electron number density in the wake region of a vehicle. A frequency-dependent finite-difference time-domain (FD2TD) method was adopted as numerical simulation method of electromagnetic waves, and properties of plasma around a vehicle, which were obtained by the simulation of flows around the vehicle with strong shock wave. The behaviors of electromagnetic waves around a vehicle were evaluated. Moreover, the numerical results of plasma attenuation were compared with those of an experiment between the ARD and a data relay satellite to evaluate the predictive performance of surface catalytic models.

Event date： 2017.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：京都工芸繊維大学   Country：Japan  

Event date： 2017.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：京都工芸繊維大学   Country：Japan  

Event date： 2017.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：京都工芸繊維大学   Country：Japan  

Event date： 2017.6

Language：English  

Venue：Denver   Country：United States  

Numerical simulations of plasma flows and electromagnetic waves around a reentry vehicle were performed to estimate the radio-frequency blackout. The plasma flows in the shock layer and wake region were calculated using computational fluid dynamics technique. The simulation of electromagnetic waves around a reentry vehicle was conducted using a frequency-dependent finite-difference time-domain method with the plasma properties obtained by computational fluid dynamics. The numerical simulations were performed for the atmospheric reentry demonstrator at various altitudes based on the reentry orbit data. Three cases of the numerical simulations, i.e., an axisymmetric model, a three-dimensional model with non-catalytic wall and finite-catalytic wall, were performed for evaluating the effects of angle of attack and catalytic wall on the radio-frequency blackout. The formations for the number density of electrons that is an important parameter in evaluating the radio-frequency blackout were greatly changed by these three cases. The simulation model was validated based on the signal loss history of the experimental flight data. The simulation results using a three-dimensional model with finite-catalytic wall showed better agreement with the measured results compared to other two cases.

Event date： 2017.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神奈川県横須賀市　ヴェルクよこすか   Country：Japan  

Three-dimensional simulation for flow fields in an arc-heated wind tunnel was developed and numerical simulation of a flow field around a columnar test piece was performed. The results were compared with those by an axisymmetric calculation. Comparison of these two cases enabled us to investigate the detailed distributions of the flow-field properties. It was clarified that the calculation of the three-dimensional model provided predictions quite similar to those of the axisymmetric calculation and thus the present code worked reasonably. In addition, it measured heat flux using the probe to have made it have an angle of attack to the arc flow to emphasize a three-dimensional effect and compered with the simulation.

Event date： 2016.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京都江戸川区　　タワーホール船堀   Country：Japan  

These days it is important to　protect　environmental　by　global　warming.　Since　the　low　mileage　becomes　important　to　car　development.
The other hand, in late years, computational fluid dynamics (CFD) become used for car development by the progress of the computer engineering.　However, a cost reduction to get enough predictability is still problem. Also we need the lattice point of hundreds of millions for CFD. Therefore, in this study, it applies an anisotropy resolving SGS model that developed by Abe in 2005. We took good agreement in Cd between CFD and Experiment by using fillet tire. However, disagreement of flow under floor and side wall flow were seen in distributions of total Cp.

Event date： 2016.12

Language：Japanese  

Venue：東京都江戸川区　　タワーホール船堀   Country：Japan  

Three-dimensional simulation　for flow field in an arc-heated wind tunnel was developed and numerical simulation of the flow field around a columnar test piece was performed with axisymmetric and three-dimensional model. Using the flow field simulation of two models, the detailed distributions of flow field properties were obtained. From comparing the results of two models, it was clarified that three-dimensional model secure about the same accuracy as axisymmetric model.

Event date： 2016.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：熊本大学   Country：Japan  

Symposium on Shock Waves in Japan

Event date： 2015.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学筑紫キャンパス   Country：Japan  

Event date： 2015.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学筑紫キャンパス   Country：Japan  

Event date： 2015.9

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

Large eddy simulation (LES) of a turbulent channel flow with wall roughness on one side was performed by adopting an anisotropy-resolving subgrid-scale (SGS) model at a shear Reynolds number Reτ=395.

Event date： 2015.9

Language：English  

Venue：Sarajevo   Country：Bosnia and Herzegovina  

Large eddy simulation (LES) of a turbulent channel flow with wall roughness on one side was performed by adopting an anisotropy-resolving subgrid-scale (SGS) model at a shear Reynolds number = 395. To investigate the grid dependency of the LES results caused by the SGS model, three grid resolutions were tested under the same definition of a roughness shape by using the immersed boundary method. The obtained results were compared with the direct numerical simulation data without roughness (flat wall) and discussed using general knowledge in this kind of flow fields as reference. The primary concern was focused on how the present SGS model could reduce the grid dependency as well as the affects of roughness on the mean velocity and turbulent stresses.

Event date： 2014.11 - 2013.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学　伊都キャンパス   Country：Japan  

本研究室にて開発した乱流の異方性を考慮した付加項をLESのサブグリッドスケールモデルに付加することによりより負荷の小さい方法で高い予測精度を保つ計算ができることを示した．

Event date： 2014.10

Language：English   Presentation type：Oral presentation (general)  

Venue：長崎市   Country：Japan  

Numerical investigation of thermal nonequilibrium inductively coupled plasma (ICP) flow was carried out to study the physical properties of the flow inside a 10-kW ICP wind tunnel with the working gas being air. The flow field was described by two-dimensional compressible axisymmetric Navier-Stokes (N-S) equations that took into account 11 species and 49 chemical reactions. A four-temperature model was adopted to model thermal nonequilibrium process in the discharge torch and vacuum chamber. The magnetic vector-potential equations were tightly coupled with the flow-field equations to describe the heating process by inductive discharge. The characteristics of air ICP flow such as thermal nonequilibrium, inductive discharge, and effects of Lorentz forces became clear through the present study.

Event date： 2014.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Nagasaki Hous Ten Bosh   Country：Japan  

Event date： 2014.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：日本電機大学北千住キャンパス   Country：Japan  

The Difference by Line of Sight in Emission Spectroscopy around Stagnation Point in an Arc Heated Wind Tunnel

Event date： 2014.6

Language：English   Presentation type：Oral presentation (general)  

Venue：Xi’an   Country：China  

Numerical investigation of nonequilibrium inductively coupled plasma (ICP) flow was carried out to study the physical properties of the flow inside a 10-kW ICP torch with the working gas nitrogen. The flow field was described by two-dimensional compressible axisymmetric Navier-Stokes (N-S) equations that took into account 5 species and 8 chemical reactions. The magnetic vector potential equations were tightly coupled with flow field equations to describe the heating process by inductive discharge. A four-temperature model was adopted to model thermal nonequilibrium process in the discharge torch. The characteristics of ICP flow such as thermal nonequilibrium, inductive discharge, strong effects of Lorentz forces become clear through the present study.

Event date： 2014.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：青山学院大学相模原キャンパス   Country：Japan  

Numerical simulation of 10-kW inductively coupled plasma (ICP) wind tunnel was carried out to study the physical properties of the flow inside the ICP torch and vacuum chamber with air as the working gas. Two-dimensional compressible axisymmetric Navier-Stokes (N-S) equations that took into account 11 species and 49 chemical reactions of air were solved. A heat source model was used to describe the heating phenomenon instead of solving the electromagnetic equations. In the vacuum chamber, a four-temperature model was coupled with N-S equations. It was found that the plasma flow in the vacuum chamber tended to be local thermochemical equilibrium.

Event date： 2013.9

Language：Japanese  

Venue：岡山大学   Country：Japan  

Spectroscopic Measurements of a Shock Wave from the Model using an Optical Fiber

Event date： 2013.6

Language：English  

Other Link： www.me.ust.hk/~ascht13

Event date： 2013.6

Language：English   Presentation type：Oral presentation (general)  

Venue：Nagoya Congress Center   Country：Japan  

We propose a new Hybrid LES/RANS Model (HLR) which combines large eddy simulation (LES) with the Reynolds-averaged Navier-Stokes (RANS) equation with the aide of an anisotropy-resolving subgrid-scale (SGS) model based on a scale-similarity model 4). We find that the introduction of an SGS anisotropic term give a reasonable influence on the transition between RANS and LES. To investigate the model performance, the proposed model is applied to fully-developed plane channel flows with various grid resolutions and at several Reynolds numbers. For further investigation, we apply the present model to high Reynolds-number complex turbulent flows of practical interest. The Ahmed body with the 25° angle of the rear slant which the Reynolds number based on length of is Re=2.78×10⁶ is selected for verification of the present model. For the flow structure, the result of HLR model shows similar to that of experiment in coarse and fine grid. The value of the friction drag coefficient of HLR model has a smaller the grid dependence than that of LES and corresponds to that of experimental. However, the pressure drag is underestimated. As the result, the drag coefficient of Ahmed body is underestimated.

Event date： 2013.5

Language：English   Presentation type：Oral presentation (general)  

Venue：Sun Moon Lake Teachers' Hostel, Nantou   Country：Taiwan, Province of China  

Numerical simulation of the flow fields was performed for the mission of Apollo AS-202 to investigate the influence of the laminar-turbulent transition position in the boundary layer around a reentry capsule on the heat flux at the wall. For this purpose, we intentionally varied the laminar-turbulent transition position and the obtained results were compared. It turned out that the transition position had a big influence on the heat flux at the wall in the forebody region. On the other hand, in the afterbody region, some discrepancies were seen compared with the experimental data. This is thought to be caused by the lack of considering the effects of the radiation heating and the radiation equilibrium, as well as the axisymmetric flow assumption.

Other Link： http://2013apcats.me.nctu.edu.tw/

Event date： 2013.5

Language：English   Presentation type：Oral presentation (general)  

Venue：the Graduat School of Harbin Institute of Technology (Shenzhen Branch)   Country：China  

The numerical simulation of flow field around HAYABUSA capsule with light-weight ablator thermal response coupled with pyrolysis gas flow inside ablator was carried out. In addition, the radiation from high temperature gas around the capsule was tightly- coupled with flow field. The HAYABUSA capsule reentered the atmosphere about 12 km/sec in velocity and Mach number about 30. During such an atmospheric entry, space vehicle is exposed very savior aerodynamic heating due to convection and radiation. In this study, HAYABUSA capsule was treated as a typical model of the atmospheric entry spacecraft.　The light-weight ablator had porous structure, and permeability was an important parameter to analyze flow inside ablator. In this study, permeability was a variable parameter depended on density of ablator. It found that the effect of permeability of light-weight ablator was important with present analysis.

Other Link： http://www.isaif11.org

Event date： 2013.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：北九州国際会議場   Country：Japan  

アーク加熱風洞での軽量アブレータの加熱試験の様子をより再現するために軽量アブレータの特徴である内部の流れを様子を温度による透過率変化をパラメータの一つとして導入することにより高精度な数値シミュレーションを外部の流れとともにカップリングさせて行いこの取り扱いの必要性を明らかにした．

Event date： 2013.1 - 2013.2

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Venue：名古屋大学   Country：Japan  

衛星の軌道修正用の小型のアークジェット推進機内部の弱電離気体がノズルから排出するまでの熱的および化学的に非平衡な流れ場の様子を簡単なモデルを用いることにより明らかにした．

Event date： 2012.11

Presentation type：Oral presentation (general)  

Venue：長崎   Country：Japan  

Numerical study of Heat-Resistance Performance for Thermochemical Non-equilibrium Flow around a Supserorbital Re-entry Capsule

Event date： 2012.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：同志社大学   Country：Japan  

Hayabusa再突入カプセルの再突入環境をモデルにとり，熱防御システムとして近年開発が進んでいる軽量アブレータを用いた場合どのようになるか，また，従来のアブレータとどのような違いが出て何に注意しながら耐熱設計をしなければならないかを論じた．

Event date： 2012.9

Presentation type：Oral presentation (general)  

Venue：金沢大学   Country：Japan  

Event date： 2012.3 - 2012.5

Presentation type：Oral presentation (general)  

Venue：千葉県　柏市   Country：Japan  

Thermal-response analysis and an arc-heated wind tunnel experiment were carried out to study the effect of the pyrolysis gas flow inside the heating ablator. The analysis treated the heating process of arc-heater and the thermal-response analysis code included heat conduction, pyrolysis of resin, pyrolysis gas flow, and surface recession due to chemical reactions. In this study, the pyrolysis gas flow was treated as the multi-dimensional (axisymmetric) and unsteady phenomenon. This computation showed that the detailed analysis considering the multi-dimensional pyrolysis-gas flow and the flow injection of pyrolysis gas led to improvement of the predictive performance for the ablator thermal response.
In addition, the temperature measurements inside and surface of the light-weight ablator were carried out. It was used two type ablator in this experiment. As for one, surfaces were coated and the other was non-coated.

Event date： 2012.1

Language：English  

Venue：Nashville, TN   Country：United States  

Turbulent plasma flows in arc heaters such as JAXA 750 kW, NASA 20 MW and Kyushu University 20 kW facilities were investigated and the distributions of flow-field properties were successfully obtained. For this purpose, an integrated analysis model to simulate various-scale arc-heated flows with high accuracy was developed. The turbulent flow field was described by the Navier-Stokes equations with a multitemperature model, which was tightly coupled with electric-field and radiation-field calculations. An accurate and low-cost radiation model and a low-Reynolds number two-equation turbulence model were introduced into the flow-field simulation. Arc discharge in constrictor section and expansion processes in nozzle section play key roles for forming an arc-heated flow. Thus, it is important to correctly model those phenomena for predicting the high-enthalpy flow properties accurately. To validate the present numerical model, the computed results were compared with the corresponding experimental data for the mass-averaged enthalpy, temperatures and number density. Through the comparison of the predicted results with detailed experimental data obtained by spectroscopic and laser-induced fluorescence techniques, the present integrated analysis model was validated. In addition, the mechanisms of energy input by discharge and energy loss were discussed with distributions of the temperature and heat flux derived from the arc column. Although it was indicated that more detailed discharge model is possibly required in order to describe arc discharge with higher accuracy, the present flow-field model was found to give generally good agreement for various operating conditions of the facilities.

Event date： 2011.12

Presentation type：Oral presentation (general)  

Venue：神奈川県　相模原市   Country：Japan  

Numerical study of Heat-Resistance Performance for Thermochemical Non-equilibrium Flow around a Supserorbital Re-entry Capsule

Event date： 2011.9

Presentation type：Oral presentation (general)  

Venue：京都大学   Country：Japan  

Event date： 2011.6

Presentation type：Oral presentation (general)  

Venue：沖縄コンベンションセンター   Country：Japan  

Event date： 2011.3

Presentation type：Oral presentation (general)  

Country：Japan  

Improvement of Predictive Performance of Thermal-Response Analysis with Pyrolysis Gas Flow inside in Ablator

Event date： 2011.3

Presentation type：Oral presentation (general)  

Venue：青山学院大学相模原キャンパス   Country：Japan  

Experimental and numerical studies of spalled particles ejected from a light-weight ablator

Event date： 2010.12 - 2011.12

Presentation type：Oral presentation (general)  

Venue：宇宙科学研究所   Country：Japan  

Event date： 2010.12

Presentation type：Oral presentation (general)  

Venue：宇宙科学研究所   Country：Japan  

Event date： 2010.11

Presentation type：Oral presentation (general)  

Venue：九州大学伊都キャンパス   Country：Japan  

Event date： 2010.11

Presentation type：Oral presentation (general)  

Venue：九州大学伊都キャンパス   Country：Japan  

Event date： 2010.9 - 2010.10

Language：English  

Venue：Prague   Country：Czech Republic  

During atmospheric entry, thermal protection material (ablator) is strongly heated by aerodynamic heating. Due to this fact, micro-order particles are generated and ejected from an ablator surface, which is called 'Spallation'. In the previous ground experiments in an arc-heated facility, the presence of spalled solid particles has been confirmed upstream of a detached shock wave or a stagnation-point boundary layer. Spallation phenomena are considered to be a possible cause of increasing heat-transfer rates on an ablator surface in the downstream region. To estimate the effect of a spalled particle on an ablator, correct values of particle parameters (e.g., size, flight velocity, position) are needed. Therefore, we carried out the heating experiment for a trial manufactured light-weight ablator, and then detailed parameters for each particle were analyzed directly from the visualized pictures. As for the visualization method, the in-line holography method, that uses a recorded hologram pattern appearing behind of an illuminated particle by a collimated laser beam, was applied to evaluate the particle parameters. Moreover, the flight path of a single spallation particle was also numerically analyzed in the present study. As a result, some particles ejected from an ablator surface were visualized in the upstream region and their parameters were evaluated successfully. This fact indicates the availability of the in-line holography method for evaluation of spallation-particle parameters. By using the obtained particle parameters, the effect of a spalled particle on an ablator surface was estimated.

Event date： 2010.9 - 2010.10

Presentation type：Oral presentation (general)  

Venue：Prague   Country：Czech Republic  

Event date： 2010.9

Language：English  

Venue：Nice   Country：France  

Turbulent plasma flow in large-scale arc heater such as NASA 60 MW Interaction Heating Facility was numerically investigated and the distribution of the arc-heated flow-field properties were successfully obtained.The turbulent flow-field was described by the Reynolds- Averaged Navier-Stokes equations with a multitemperature model,tightly coupled with the electric field and the radiation-field calculations. In addition,an accurate and low-cost radiation model and a low-Reynolds number two-equation turbulence model were introduced into the flowfield simulation.It was quantitatively clarified that radiation and turbulence phenomena are very important mechanisms to transfer heat and momentum from high-temperature core region to cold gas region near the wall.To validate the present numerical model,the numerical solutions were compared with the experimental data,e.g.,arc voltage,mass-averaged enthalpy,chamber pressure and heat efficiency.It was indicated that the present flow-field simulation model showed good agreement over various operating conditions of the facilities.

Event date： 2010.9 - 2009.9

Presentation type：Oral presentation (general)  

Venue：名古屋工業大学   Country：Japan  

Thermal Response of Light-weight Ablator under Arc-heated flow

Event date： 2010.3

Presentation type：Oral presentation (general)  

Venue：埼玉大学   Country：Japan  

Event date： 2010.3

Presentation type：Oral presentation (general)  

Venue：埼玉大学   Country：Japan  

Visualization experiment of spallated particles ejected from a light-weight ablator

Event date： 2009.12 - 2010.12

Presentation type：Oral presentation (general)  

Venue：宇宙科学研究所   Country：Japan  

Event date： 2009.12

Presentation type：Oral presentation (general)  

Venue：宇宙科学研究所   Country：Japan  

Event date： 2009.12

Presentation type：Oral presentation (general)  

Venue：北九州市コンベンションセンター   Country：Japan  

Event date： 2009.11

Presentation type：Oral presentation (general)  

Venue：Hungshan China   Country：China  

Event date： 2009.10

Presentation type：Oral presentation (general)  

Venue：Jeju   Country：Korea, Republic of  

Event date： 2009.9

Presentation type：Oral presentation (general)  

Venue：Nice　Acropolis center   Country：France  

Event date： 2009.9

Presentation type：Oral presentation (general)  

Venue：岩手大学   Country：Japan  

Event date： 2009.7

Presentation type：Oral presentation (general)  

Venue：Tukuba   Country：Japan  

Event date： 2009.6

Presentation type：Oral presentation (general)  

Venue：筑波コンベンショナルセンター   Country：Japan  

Event date： 2008.7

Language：English  

Venue：Kyoto   Country：Japan  

Numerical simulation is carried out and the distribution of flow field properties is obtained for nonequilibrium flow in a constrictor-type 20kW arc-heated wind tunnel. In the arc heater, plasma flow is highly in nonequilibrium and arc discharge plays a critical role. The flow field is described by the Navier-Stokes equations with a multi-temperature model. The flow field equations are solved with the governing equation for the electric field being coupled. Furthermore, to validate the present numerical model, the numerical solutions are compared with the corresponding experimental data. The flow characteristics in the 20kW arc heater, e.g., the arc charge and the supersonic expansion, become clear through the present simulation. Moreover, the computed results for the arc heater indicate almost full dissociation/ ionization reactions and thermochemical equilibrium in the constrictor part, while strong nonequilibrium clearly appears in the nozzle section.

Event date： 2008.3

Presentation type：Oral presentation (general)  

Venue：東京都目黒区   Country：Japan  

Numerical Simulation of Chemical Nonequilibrium Flows Around a Jovian Entory Probe

Event date： 2008.3

Presentation type：Oral presentation (general)  

Venue：東京都目黒区   Country：Japan  

Numerical Investigation of Thermochemical Nonequilibrium Flow Field in a 20kW Arc Heater Coupled with Electric Field Calculation

Event date： 2007.12

Presentation type：Oral presentation (general)  

Venue：Kyoto city   Country：Japan  

Numerical Simulation of Plasma Flows in a 20kW Arc-heated Wind Tunnel Using Multi-temperature Model

Event date： 2007.3

Presentation type：Oral presentation (general)  

Venue：福岡県春日市   Country：Japan  

Numerical Simulation of Thermochemical Nonequilibrium Flow in an Arc-Heated Wind Tunnel

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：名古屋大学東山キャンパス   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Measurements of velocity field behind a small-type wind turbine

Presentation type：Oral presentation (general)  

Venue：大阪   Country：Japan  

A Thermochemical Nonequilibrium Nozzle Flow of Arc-Heated Air

Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

A Basic Study of Spallation Phenomena in Ablating Heat Shielde

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：名古屋大学東山キャンパス   Country：Japan  

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Number of participants：1,000

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Number of participants：800

Type：Competition, symposium, etc.