JAXA Supercomputer System Annual Report February 2023-January 2024

Report Number: R23EEG60100

Subject Category: Research and Development

PDF available here

• Responsible Representative: Shuto Yatsuyanagi, Research and Development Directorate, Research Unit IV
• Contact Information: Shuto Yatsuyanagi(yatrsuyanagi.shuto@jaxa.jp)
• Members: Shuto Yatsuyanagi

Abstract

A laminar-turbulent transition at the surface of a re-entry vehicle is an important issue for the design of a Thermal Protection System (TPS). Since the heat transfer coefficient in the turbulent boundary layer is several times higher than that in the laminar boundary layer, the location of the laminar-turbulent transition point is a crucial design parameter for the TPS. Currently, the transition process is not yet understood, and the actual design assumes a turbulent boundary layer along the entire flight path and allows excessive TPS weight. The objective of this project is to elucidate the transition process on the surface of the re-entry vehicle by numerical simulation on JSS3 and to obtain knowledge that will contribute to the weight reduction of the TPS.

Reference URL

N/A

Reasons and benefits of using JAXA Supercomputer System

Since the laminar-turbulent transition is closely related to the growth process of small disturbances in the airflow, its numerical simulation requires high spatio-temporal resolution. To achieve numerical simulations with high spatio-temporal resolution, it is essential to use a large amount of computational resources such as JSS3.

Achievements of the Year

A high-order accuracy numerical method has been developed for simulating disturbance growth and transition processes in high-temperature hypersonic flows (Fig. 1).

The effect of freestream disturbances on the disturbance growth process over a blunt body was evaluated. Fig. 2 shows developing two-dimensional waves, which was considered to be a Kelvin-Helmholtz (KH) instability, but it did not collapse and its effect on the wall heat flux was small (Fig. 3). Recent attempts include an evaluation of the wall roughness effects on the disturbance growth and a numerical analysis of the coupling of wall roughness-induced disturbances and freestream disturbances.

Fig.1: High temperature hypersonic flow at Mach number 7.7 around the Apollo capsule

Fig.2: Iso-surface of near-wall Q-criterion (Q =1e-4) colored by fluid temperature

Fig.3: Heat flux distributions on the heatshield side of the Apollo capsule model

Publications

– Oral Presentations

1) Shuto Yatsuyanagi, Hideyuki Tanno, “Flow characteristics of super-orbital expansion tube HEK-X,” Symposium on Flight Mechanics and Astrodynamics, (2023).

2) Shuto Yatsuyanagi, Hideyuki Tanno, “Numerical Simulation of Boundary Layer

Usage of JSS

Computational Information

• Process Parallelization Methods: MPI
• Thread Parallelization Methods: N/A
• Number of Processes: 912 – 3264
• Elapsed Time per Case: 72 Hour(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 0.65

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 2023-January 2024