Research on Fundamental Aerodynamics in Real-World Environments

JAXA Supercomputer System Annual Report February 2025-January 2026

Report Number: R25EDA201J99

Subject Category: Aeronautical Technology

Responsible Representative: Nakita Kazuyuki, Aviation Technology Directorate, Fundamental Aeronautics Research Unit
Contact Information: Yuki Ide, Chanteux Xavier(ide.yuki@jaxa.jp, chanteux.xavier@jaxa.jp)
Members: Xavier Chanteux, Lusher David, Tokugawa Naoko, Ohhira Keisuke, Ide Yuki

Abstract

The project aims to improve understanding of the boundary-layer laminar-to-turbulent transition process in low-turbulence environment such as wind tunnel or flight conditions. One of the items of this project investigates the influence of free-stream turbulence on the transition using CFD (DNS).

Reference URL

N/A

Reasons and benefits of using JAXA Supercomputer System

Numerical investigation of boundary-layer receptivity to free-stream turbulence requires solving the Navier-Stokes equations over fine grids (DNS) to capture the law scales structures involved in the transition process.

Achievements of the Year

The main achievement of the year is the DNS of an incompressible flow around a NACA0008 airfoil at Reynolds number 0.5 million using up to 12 GPUs (and 6000 CPUs) on a C-grid of 326 million points. This simulation allowed to validate the implementation of an isotropic and homogeneous free-stream turbulence generator, necessary step for the research project. Similar simulations allowed to investigated grid sensibility of the results and gain experience in using the newly implemented tool.

Fig.1: Mesh distribution around the NACA0008 airfoil and zoom on the leading edge. The blue zone around x=-0.6 is the position of the forcing. Only one every seven points are plotted

Fig.2: Wall normal view of the streamwise velocity perturbation, where blue and red areas represent negative and positive values, respectively. The solid line shows to the boundary-layer thickness. Isotropic and homogeneous turbulence is visible in the free-stream, in opposition to streaky perturbations inside the boundary-layer.

Fig.3: 3D visualization of the flow field. Pseudocolors represent the streamwise velocity perturbations outside the boundary layer. Streaks are visualised by selecting iso-contours at ±0.01.

Publications

N/A

Usage of JSS

Computational Information

Process Parallelization Methods: MPI
Thread Parallelization Methods: CUDA
Number of Processes: 8 - 12
Elapsed Time per Case: 84 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	2781646.03	0.13
TOKI-ST	8662.92	0.01
TOKI-GP	112970.96	1.82
TOKI-XM	50850.78	17.47
TOKI-LM	64.47	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	102400.00	0.67
/ssd	0.00	0.00

Archiver Resources
Archiver Name	Storage Used (TiB)	Fraction of Usage*2(%)
J-SPACE	1.75	0.01

*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)	305.33	0.21

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