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Analyses of Hypersonic Flows around Capsules and Attitude Instability of Capsules

JAXA Supercomputer System Annual Report February 2023-January 2024

Report Number: R23EDA201A32

Subject Category: Aeronautical Technology

PDF available here

  • Responsible Representative: Kenji Fujii, Aviation Technology Directorate, Fundamental Aeronautics Research Unit
  • Contact Information: Takashi Ozawa(ozawa.takashi@jaxa.jp)
  • Members: Takashi Ozawa, Yoshihiro Shimizu, Takaki Uwazumi

Abstract

In this study, we try to enhance physical models for high temperature gas and numerical simulation method to accurately predict heating and aerodynamic characteristics at atmospheric entry. We aim to develop high fidelity simulation tool by demonstrating improvement of prediction accuracy by comparing experimental data and simulation results with the newly proposed model and method. In this year, we focus on the analysis of hypersonic flows inside a shock tube and around capsules in addition to attitude instability analysis for sample return capsules.

Reference URL

N/A

Reasons and benefits of using JAXA Supercomputer System

In order to evaluate uncertainties and dependence on nonequilibrium thermochemical models, configurations, and freestream conditions, supercomputer has been used to perform a large number of CFD runs by changing physical models, configurations, and flow conditions.

Achievements of the Year

In this study, qualitative evaluations of the rate coefficient for CO2 recombination reactions that occurs behind the Mars atmospheric entry capsule was conducted by comparing shock tube experiments and flow calculations using the JONATHAN code. In general, the backward rate coefficients of the chemical reactions are calculated from the detailed balance law, assuming chemical equilibrium. However, in environments where significant nonequilibrium is expected, such as capsule wake, there is no guarantee that the backward rate calculated from the detailed balance law is correct. Therefore, we attempeted to predict IR radiation intensity by experiment and calculation. For the experiment, IR radiation of a nonequilibrium flow created by a shock tube with the expansion nozzle(Fig.1), was measured. For the calculation, the intensity of IR radiation calculated using the JONATHAN code and SPRADIAN(Fig.2) were used. As a result, a difference was observed between the experimental and calculated intensity of IR radiation obtained in the downstream window in the nozzle(Fig.3). This suggests that the CO2 recombination reaction rate coefficient in the nonequilibrium environments may be larger than the value obtained by detailed balance law. We have also studied size dependence and Mach number dependence (M=0.8, 1.0, and 1.2) (Fig.4) of pitch motion of Hayabusa-type capsules using the JONATHAN-ALE code with Large-Eddy Simulation (LES).

Annual Reoprt Figures for 2023

Fig.1: The Shock Tube with expansion nozzle.

 

Annual Reoprt Figures for 2023

Fig.2: A pressure contour diagram of shock wave flowing through expansion nozzle.

 

Annual Reoprt Figures for 2023

Fig.3: Comparison of IR radiation intensity between experiments and calculations

 

Annual Reoprt Figures for 2023

Fig.4: Comparison of angle of attack history among M=0.8, 1.0 and 1.2 mm with a D=400mm hayabusa-type capsule

 

Publications

– Oral Presentations

The 34th International Symposium on Space Technology and Science

Proceedings of the Fluid Mechanics Conference:2023

Proceedings of the Space Sciences and Technology Conference: 2023

Symposium on Flight Mechanics and Astrodynamics: 2023

Usage of JSS

Computational Information

  • Process Parallelization Methods: MPI
  • Thread Parallelization Methods: OpenMP
  • Number of Processes: 366 – 2928
  • Elapsed Time per Case: 24 Hour(s)

JSS3 Resources Used

 

Fraction of Usage in Total Resources*1(%): 2.62

 

Details

Please refer to System Configuration of JSS3 for the system configuration and major specifications of JSS3.

Computational Resources
System Name CPU Resources Used
(Core x Hours)
Fraction of Usage*2(%)
TOKI-SORA 71350306.03 3.22
TOKI-ST 0.00 0.00
TOKI-GP 0.00 0.00
TOKI-XM 0.00 0.00
TOKI-LM 0.00 0.00
TOKI-TST 0.00 0.00
TOKI-TGP 0.00 0.00
TOKI-TLM 0.00 0.00

 

File System Resources
File System Name Storage Assigned
(GiB)
Fraction of Usage*2(%)
/home 163.33 0.14
/data and /data2 3380.00 0.02
/ssd 0.00 0.00

 

Archiver Resources
Archiver Name Storage Used
(TiB)
Fraction of Usage*2(%)
J-SPACE 0.00 0.00

*1: Fraction of Usage in Total Resources: Weighted average of three resource types (Computing, File System, and Archiver).

*2: Fraction of Usage:Percentage of usage relative to each resource used in one year.

 

ISV Software Licenses Used

ISV Software Licenses Resources
ISV Software Licenses Used
(Hours)
Fraction of Usage*2(%)
ISV Software Licenses
(Total)
0.00 0.00

*2: Fraction of Usage:Percentage of usage relative to each resource used in one year.

JAXA Supercomputer System Annual Report February 2023-January 2024