JAXA Supercomputer System Annual Report February 2025-January 2026

Report Number: R25ECMP26

Subject Category: Competitive Funding

PDF (to be added)

• Responsible Representative: Kazuyuki Nakakita, Aviation Technology Directorate, Fundamental Technology Research Unit
• Contact Information: Andrea Sansica(sansica.andrea@jaxa.jp)
• Members: Haruyuki Kakimoto, Keiichi Kitamura, Tomohiro Mamashita, Sora Yasui, David Lusher, Andrea Sansica

Abstract

In this study, we move from the MUSCL framework and use the MUSCL-THINC method, which gives the physical quantity distribution within a numerical cell as a hyperbolic function, allowing to sharply capture shock wave discontinuities.

Reference URL

N/A

Reasons and benefits of using JAXA Supercomputer System

The effectiveness of the method will be investigated by applying it to various flow configurations such as multiphase flow, electromagnetic fluid, and transonic buffet. These simulations require significant computational power, and therefore the use of JAXA supercomputer is necessary.

Achievements of the Year

The THINC method was originally proposed for multiphase flow interfaces, but preliminary calculations have shown that it is also effective for suppressing the diffusion of weak shock waves such as Mach 1.01. Although this method is an efficient spatial second-order precision method, it achieves a numerical solution with a resolution equivalent to the spatial fifth-order precision, and reduces three to five times the computational cost. In this year, the unstructured grid extension of MUSCL-THINC is pursued (not completed, though). At the same time, as test cases for future comparison purpose, near Mach 1.01 and related unsteady aerodynamic simulations have been conducted without THINC.

Simulations using FaSTAR have been carried out to determine the sensitivity of buffet predictions to numerical scheme accuracy (see Figure 1).

Fig.1: Buffet prediction sensitivity to numerical scheme accuracy

Publications

- Non peer-reviewed papers

1) A. Sansica, D.J. Lusher, K. Kitamura, G. Fukushima. Sensitivity Analysis of Turbulent Transonic Buffet to Scheme Accuracy of Turbulent Fluxes and U-MUSCL Method in Finite Volume Solvers. The 35th International Symposium on Shock Waves, (Brisbane, Australia, 2025 July).

- Oral Presentations

1) A. Sansica, D.J. Lusher, K. Kitamura, G. Fukushima. Sensitivity Analysis of Turbulent Transonic Buffet to Scheme Accuracy of Turbulent Fluxes and U-MUSCL Method in Finite Volume Solvers. The 35th International Symposium on Shock Waves, (Brisbane, Australia, 2025 July).

2) Kakimoto, H., Kitamura, K., and Nonaka, S.: Numerical Investigation of Transonic Aerodynamic Characteristics of a Slender Body with a Surface Protuberance Using Delayed and Zonal Detached Eddy Simulations, 39th Computational Fluid Dynamics Conference, [OS3-3-2-05], Dec-16-2025.

3) Kitamura, K., Z.-N. Wang, F.M. Moller, P.G. Tucker: Numerical Investigations on DES-Family and Upwind/Central-Differencing Scheme in Shock/Boundary-Layer Interactions, Gas Turbine Society of Japan 53rd Annual Congress, A-20, Oct-09-2025.

Usage of JSS

Computational Information

• Process Parallelization Methods: MPI
• Thread Parallelization Methods: N/A
• Number of Processes: 48 - 512
• Elapsed Time per Case: 24 Hour(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 0.12

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