JAXA Supercomputer System Annual Report February 2025-January 2026

Report Number: R25EDA201J05

Subject Category: Aeronautical Technology

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

Abstract

There is a strong need to incorporate LES that can reproduce combustion and turbulence phenomena with high fidelity into the design process in order to enhance the efficiency of the development of aerospace propulsion systems such as aero engines and rocket engines. However, LES is not widely incorporated into the design process in actual development because it requires three-dimensional analysis and is computationally very expensive. This study aims to reduce the dimension of combustion and turbulence LES, which inherently requires three-dimensional computation, through two-dimensional modeling. The goal is to achieve a two-dimensional LES and reduce the cost to a level where it can be used in the design of propulsion systems.

Reference URL

N/A

Reasons and benefits of using JAXA Supercomputer System

High-fidelity combustion LES data is required for modeling a combustor that is dominated by three-dimensional physical phenomena using a two-dimensional approximation, but combustion LES requires solving the governing equations for a large number of chemical species produced by chemical reactions as a three-dimensional unsteady problem. Such an analysis is computationally very expensive and cannot be performed without the use of a supercomputer.

Achievements of the Year

We performed LESs of Mach 6 scramjet combustion tests conducted at the Ramjet Engine Test Facility (RJTF). Results are reported for the M6S case, where no water vapor is present in the test flow due to the use of a thermal storage heating. Figure 1 shows the instantaneous flow field result from a non-combustion simulation without ethylene fuel injection. Figure 2 shows the comparison of wall pressure distributions evaluated from the time-averaged flow field with experimental data. Although the experimental data show an asymmetric distribution between the top and bottom walls of the combustion chamber, the LES results generally reproduce the trends observed in the experimental data. Figure 3 shows the instantaneous flow field results from a combustion simulation performed with ethylene fuel injection (equivalent ratio = 0.35). Figure 4 shows the comparison of wall pressure distributions from the combustion LES with experimental data. While the LES trends generally agree with the experimental data upstream of the cavity, the wall pressures from the LES were significantly underestimated downstream of the cavity.

Fig.1: Instantaneous Mach number contours at z = 0 mm of non-combustion LES analysis for M6S condition (no water vapor).

Fig.2: Comparison of LES and experimental data on wall pressure for non-combustion case.

Fig.3: Instantaneous Mach number contours at z = 0 mm of combustion LES analysis for M6S condition (no water vapor).

Fig.4: Comparison of LES and experimental data on wall pressure for combustion case.

Publications

- Non peer-reviewed papers

1) Shingo Matsuyama, "Post-flight Analysis of S-520-RD1 Flight Experiment Data", Proceedings of the 57th Fluid Dynamics Conference / the 43rd Aerospace Numerical Simulation Symposium, SP-25-010, p. 95-100, 2026.

- Oral Presentations

1) Shingo Matsuyama, "Post-flight Analysis of S-520-RD1 Flight Experiment Data", the 57th Fluid Dynamics Conference / the 43rd Aerospace Numerical Simulation Symposium, 2025.

2) Shingo Matsuyama, "Large-Eddy Simulation of Scramjet Combustion Test at Mach 6 by RJTF", the 63rd Symposium (Japanese) on Combustion, 2025.

Usage of JSS

Computational Information

• Process Parallelization Methods: MPI
• Thread Parallelization Methods: OpenMP
• Number of Processes: 102 - 305
• Elapsed Time per Case: 400 Hour(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 1.01

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