JAXA Supercomputer System Annual Report February 2025-January 2026

Report Number: R25EDA201J08

Subject Category: Aeronautical Technology

PDF (to be added)

• Responsible Representative: Kazuyuki Nakakita, Aviation Technology Directorate, Fundamental Aeronautics Research Unit
• Contact Information: Shingo Matsuyama(matsuyama.shingo@jaxa.jp)
• Members: Shingo Matsuyama

Abstract

In recent years, research and development on reusable rockets has been proceeding vigorously, and it is expected that many new technologies not used in conventional expendable rockets—such as rocket retropropulsion and grid fins—will be adopted. In establishing these core technologies, there is a strong expectation that CFD simulations will be utilized in addition to wind tunnel and flight tests. This research aims to advance CFD analyses applied to reusable rockets, including rocket retropropulsion and attitude control using grid fins.

Reference URL

N/A

Reasons and benefits of using JAXA Supercomputer System

CFD simulations of rocket retropropulsion and flight control using grid fins require three-dimensional analysis involving complex geometries. Furthermore, when accounting for chemical reactions caused by combustion gases, analyses involving numerous chemical species—including fuel, oxidizers, and combustion products—are required. Additionally, to evaluate the performance of retropropulsion and grid fins, it is necessary to conduct an extensive number of analyses by varying parameters such as thrust conditions and fin shapes. Such analyses are computationally intensive and cannot be performed without the use of a supercomputer.

Achievements of the Year

LES analyses were performed on hypersonic wind tunnel tests of hypersonic retropropulsion conducted in NASA's Unitary Plan Wind Tunnel (Mach 4.6) and 31-Inch Mach 10 Air Tunnel (Mach 9.8). The accuracy of LES analyses was verified by comparing them with experimental data. LESs were performed by varying the jet stagnation pressure under a model angle of attack of 0-degree (Figures 1 and 2), and the results showed that LES accurately reproduced the experimental data for both Mach 4.6 and 9.8 (Figures 3 and 4).

Fig.1: LES results for the instantaneous flow field for M = 4.6. Pseudo-Schlieren images are shown using the instantaneous density gradient field.

Fig.2: LES results for the instantaneous flow field for M = 9.8. Pseudo-Schlieren images are shown using the instantaneous density gradient field.

Fig.3: Comparison of LES and wind tunnel test data for M = 4.6. Lj and Ls represent the height of the jet plume and the standoff distance of the bow shock, respectively.

Fig.4: Comparison of LES and wind tunnel test data for M = 9.8. Lj and Ls represent the height of the jet plume and the standoff distance of the bow shock, respectively.

Publications

- Oral Presentations

1) Shingo Matsuyama, "LES of Hypersonic Retropropulsion", Symposium on Flight Mechanics and Astrodynamics: 2025, 2025.

2) Shingo Matsuyama, "LES of Hypersonic Retropropulsion", Symposium on Shock Waves in Japan, 2026.

Usage of JSS

Computational Information

• Process Parallelization Methods: MPI
• Thread Parallelization Methods: OpenMP
• Number of Processes: 98 - 196
• Elapsed Time per Case: 24 Hour(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 0.04

Details

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

*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

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

JAXA Supercomputer System Annual Report February 2025-January 2026