CFD and CFD-DEM coupled simulation for a large-scale PSI test

JAXA Supercomputer System Annual Report February 2025-January 2026

Report Number: R25EEE21100

Subject Category: Space Exploration

Responsible Representative: Kota Tanabe, JAXA Space Exploration Center, Space Exploration System Technology Unit
Contact Information: Mitsuhisa Baba(baba.mitsuhisa@jaxa.jp)
Members: Mitsuhisa Baba, Arnaud Delibie

Abstract

There is a risk that during spacecraft take-off and landing, large amounts of regolith will be scattered from the ground by the engine exhaust plume and that craters will be formed. We will develop technology to properly assess this risk and provide feedback to the spacecraft itself and its operations.

Reference URL

N/A

Reasons and benefits of using JAXA Supercomputer System

In addition to unsteady CFD analysis, coupled discrete element method (DEM) analysis is very computationally costly. Therefore, large-scale parallel computing using a supercomputer is effective.

Achievements of the Year

NASA Langley Research Center is planning a large-scale ground experiment of PSI for a lunar lander.

JAXA conducted joint research with NASA and used CFD and CFD-DEM coupled analysis to predict the results of the large-scale experiment. The results indicated that a large crater could be formed in a very short time.

Fig.1: One of the numerical analysis assuming large-scale experiments at NASA Langley Research Center

Publications

N/A

Usage of JSS

Computational Information

Process Parallelization Methods: MPI
Thread Parallelization Methods: MPI
Number of Processes: 150 - 3600
Elapsed Time per Case: 168 Hour(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 0.25

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	1558831.05	0.07
TOKI-ST	1714481.32	1.78
TOKI-GP	0.00	0.00
TOKI-XM	1.34	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	0.00	0.00
/data and /data2	0.00	0.00
/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.