Computational Fluid Dynamics Analysis of Supersonic Aircraft

JAXA Supercomputer System Annual Report February 2025-January 2026

Report Number: R25EACA20

Subject Category: JSS Inter-University Research

Responsible Representative: Keiichi Kitamura, Professor, Yokohama National University
Contact Information: Hiromu Sunazuka(sunazuka-hiromu-jx@ynu.jp)
Members: Keiichi Kitamura, Yuki Oonawa, Hiromu Sunazuka

Abstract

It is important to accurately understand the aerodynamic characteristics of rocket vehicles and deceleration devices for reducing the cost of space transportation and advancing planetary exploration technologies. In particular, in supersonic flows accompanied by shock waves, surface protrusions on the vehicle and the shape and arrangement of parachutes can significantly affect the aerodynamic characteristics and the unsteady behavior of the flow. Therefore, it is necessary to clarify these effects in detail. In this study, numerical analyses are conducted to investigate the aerodynamic characteristics of rockets and parachutes in shock-wave-dominated flows. Specifically, we examine the effects of protrusion shapes on the side force and axial force acting on rockets, and evaluate how multiple canopy shapes influence shock-wave oscillation and drag characteristics in supersonic parachutes accompanied by shock-wave oscillation. Through this study, we aim to obtain design guidelines for rockets with protrusions and to accumulate knowledge on the optimal shapes and configurations of supersonic parachutes, thereby contributing to the future development of space transportation and Mars exploration technologies.

Reference URL

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Reasons and benefits of using JAXA Supercomputer System

We performed numerical fluid calculations to understand the aerodynamic characteristics of rockets and supersonic parachutes accompanied by shock waves. In particular, for supersonic parachutes, it is necessary to carry out large-scale numerical calculations with fine computational grids in order to reproduce the unsteady flow between the capsule and the canopy, as well as the shock-wave oscillation. In addition, for rockets with protrusions, calculations for a large number of conditions are required to investigate the effects of differences in protrusion shape on the aerodynamic characteristics. For this reason, JSS3 is used. These large-scale calculations not only enabled us to obtain the aerodynamic characteristics with high accuracy, but also to clarify the shock-wave structure and detailed flow fields, which are difficult to capture in experiments.

Achievements of the Year

Numerical fluid calculations were carried out for the unsteady flow between the capsule and the canopy using a model geometry of a supersonic parachute. This fiscal year, we mainly analyzed the temporal variations of the turbulent structures and shock-wave structures formed by the interaction between them. As a result, we were able to reproduce, through large-scale calculations using JSS3, the complex unsteady phenomena in which shock-wave oscillations and vortex structures are coupled in the flow field behind the capsule and in front of the canopy. As a representative example, Video 1 shows a visualization of the flow field under a certain condition. Focusing on the region between the capsule and the canopy, it was found that the shock-wave structure and the vortex structures in the wake vary significantly with time, indicating that the interaction between them is an important factor governing the entire flow field. These results provide useful knowledge for the shape and configuration design of supersonic parachutes.

Fig.1(video): Visualization of the temporal variation of the density-gradient distribution around a model object simulating a supersonic parachute. The flow field is shown from a direction perpendicular to the freestream under a Mach 2 uniform-flow condition.

Publications

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Usage of JSS

Computational Information

Process Parallelization Methods: MPI
Thread Parallelization Methods: N/A
Number of Processes: 1440 - 3840
Elapsed Time per Case: 120 Hour(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 0.07

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	528600.77	0.02
TOKI-ST	324704.56	0.34
TOKI-GP	0.00	0.00
TOKI-XM	0.00	0.00
TOKI-LM	1782.09	0.13
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	1024.00	1.64
/data and /data2	102400.00	0.67
/ssd	30720.00	1.87

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)	604.52	0.42

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