Development of improved numerical tools for Certification by Analysis(CbA)

JAXA Supercomputer System Annual Report February 2025-January 2026

Report Number: R25EDA201G22

Subject Category: Aeronautical Technology

Responsible Representative: Kazuyuki Nakakita, Aviation Technology Directorate, Fundamental Technology Research Unit
Contact Information: Andrea Sansica(sansica.andrea@jaxa.jp)
Members: David Lusher, Ryohei Kirihara, Kenji Hayashi, Yuki Ide, Masashi Kanamori, Tomoaki Matsuzaki, Yoimi Kojima, Yosuke Sugioka, Takahiro Yamamoto, Junpei Kakazu, Andrea Sansica

Abstract

High-accuracy simulations for stall and buffet are needed during the aircraft design. However, since the simulation cost is very high, we want to develop computation methodologies that aim at high-accuracy results with low computational cost. Hybrid RANS/LES methods (Delayed Detached Eddy Simulation; DDES) have been implemented in FaSTAR and validated for different flow configurations. We improved the accuracy of off-design stall prediction through the development of automated grid refining (AMR) technology.

Reference URL

N/A

Reasons and benefits of using JAXA Supercomputer System

For stall analysis, it is necessary to perform calculations on 3D complex geometries. Achieving high accuracy requires a large amount of computing power, so it is necessary to use a JAXA supercomputer.

Achievements of the Year

A new boundary-layer shielding function (Deck & Renard, 2020), which controls the RANS/LES transition in the DDES method, was introduced to improve separation prediction performance. As a result, the aerodynamic prediction accuracy for high-lift aircraft configurations was enhanced, leading to improved lift prediction near stall conditions (Figure 1). Furthermore, a higher-fidelity wall-modeled large eddy simulation (WMLES) method was implemented, and its performance was validated using a three-element airfoil configuration.

Using AMR, we were able to automatically generate solution-adapted grids for 3D wings (Figure 2) and full-aircraft configurations at moderate angles of attack.

Fig.1: Example of flow-field simulation around a high-lift aircraft configuration using the DDES method

Fig.2: Initial (cycle 0) and final (cycle 7) grids on the ONERA M6 wing. Adapted grids cluster points in physically relevant flow regions (i.e. shock wave and wake). Pressure distributions reported on the right indicate that adapted grids are in agreement with manual grids and experiments.

Publications

N/A

Usage of JSS

Computational Information

Process Parallelization Methods: MPI
Thread Parallelization Methods: OpenMP
Number of Processes: 48 - 1537
Elapsed Time per Case: 168 Hour(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 1.74

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	45233417.00	2.05
TOKI-ST	128344.83	0.13
TOKI-GP	39.35	0.00
TOKI-XM	12456.94	4.28
TOKI-LM	22422.31	1.69
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	21.83	0.07

*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)	1344.31	0.94

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