JAXA Supercomputer System Annual Report February 2025-January 2026

Report Number: R25EACA41

Subject Category: JSS Inter-University Research

PDF (to be added)

• Responsible Representative: Makoto Sato, Associate Professor, Kogakuin University
• Contact Information: Makoto Sato, Kogakuin University(msato@cc.kogakuin.ac.jp)
• Members: Takahumi Hirose, Yusei Iida, Yuya Kuroda, Taichi Matsumoto, Makoto Sato, Mitsuho Taniguchi, Yohei Takahashi, Hiroshi Yukita

Abstract

The ISAS/JAXA is leading a research and development project for various Mars aricrafts. In the Oyama Laboratory at the ISAS, experimental studies has been conducted to measure the aerodynamic characteristics of a Mars helicopter under low-pressure conditions simulating the Martian atmosphere. Furthermore, high-altitude flight tests for a Mars airplane has been conducted. In the present research, numerical simulations of the flow around various Mars aircrafts are coducted under the same conditions as the experiments, to elucidate the aerodynamic characteristics and flow physics.

Reference URL

N/A

Reasons and benefits of using JAXA Supercomputer System

We need to conduct the large-scale simulations on various Mars aircrafts flows using "LANS3D", "rFlow3D", "FaSTAR" and "FaSTAR-MOVE", which have been developed in JAXA.

Achievements of the Year

Following the previous year’s study, the influence of propeller–wing interaction in a Mars airplane configuration was investigated. In particular, the effect of a swirling flow, which simulates the propeller wake, on the laminar separation bubble over a wing at low Reynolds numbers was examined. In the present year, the influence of the propeller arrangement and the number of propellers on the laminar separation bubble was investigated. Based on the experimental conditions conducted at Tohoku University [1], the Reynolds number was set to 30,000. The propeller flow was modeled using the Actuator Disk Model. The numerical simulations were performed using the LANS3D solver.

Figure 1 shows the distribution of the skin-friction coefficient on the airfoil surface obtained for different propeller positions, where the propeller location was moved perpendicular to the airfoil chord direction using the Actuator Disk Model. The results indicate that the position of the propeller (ΔZ) significantly changes the region of the laminar separation bubble on the airfoil surface on both the upwash and downwash sides.

In addition, the effect of wall interference on the aerodynamic characteristics of a rotor for a Mars helicopter was investigated. Numerical simulations were conducted using rFlow3D for the hexarotor configuration of the Mars helicopter “HAMILTON” [2]. Figure 2 shows the cross-sectional distribution of the vertical velocity for different distances between the hexarotor and the wall surface. When the rotor–wall distance (g/D) is small, the downstream flow of the rotor is attracted toward the wall, and the interference between the rotors becomes more pronounced.

Furthermore, the effect of spatial confinement on the aerodynamic characteristics of a Mars helicopter rotor was investigated. The influence of three different spatial conditions—an open space (no surrounding walls), a cylindrical space (side walls only), and a closed space (side walls with the upper and lower openings closed)—on aerodynamic performance was compared through numerical simulations using FaSTAR-MOVE. Figure 3 shows the flow field in the cylindrical space, demonstrating the effect of confinement on the rotor aerodynamic performance.

[1] Okawa, M., Nishimura, R., Ikami, T., and Nagai, H., "Unsteady Propeller Wake Interference on Wing in Tractor Configuration at Low-Reynolds-Number Condition", J. Aircraft, vol.62, pp. 3-12 (2025).

[2] Sugiura, M., Tanabe, Y., Sugawara, H., Kimura, K., Oyama, A., Sato, M., Yoshikawa, K., Buto, Y., Kanazaki, M., Kishi, Y., Kikuchi, D., and Minajima, T., “Blade Shape Optimization of Mars Helicopter Exploring Pit Craters”, VFS Forum 78-paper93, (2022).

Fig.1: Effects of propeller position on distribution of the skin-friction on the airfoil surface in propeller-wing interaction

Fig.2: Effects of wall-rotor interaction on flow fields of hexarotor for Mars helicopter

Fig.3: Flow field around Mars helicopter rotor in the cylindrical space

Publications

N/A

Usage of JSS

Computational Information

• Process Parallelization Methods: N/A
• Thread Parallelization Methods: OpenMP
• Number of Processes: 1
• Elapsed Time per Case: 720 Hour(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 0.30

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