Fluid analysis for CFD workshops

JAXA Supercomputer System Annual Report February 2025-January 2026

Report Number: R25EDA201G27

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, Kenji Hayashi, Tomoaki Matsuzaki, Yoimi Kojima, Junpei Kakazu, Andrea Sansica

Abstract

Through our participation in various domestic and international workshops, we are advancing the predictive capabilities for full-aircraft configurations under stall conditions. Furthermore, we are establishing a set of best-practice guidelines aimed at maximizing both the robustness and accuracy of these numerical simulations.

Reference URL

N/A

Reasons and benefits of using JAXA Supercomputer System

For CFD workshops, it is necessary to use JAXA's supercomputers to perform a large number of calculations of three-dimensional complex shapes to achieve high accuracy.

Achievements of the Year

By conducting high-fidelity analyses focused on the CRM-HL configuration under stall conditions, we established numerical best-practices for simulating stall and buffet phenomena. Our research successfully identified specific sources of numerical error related to low-speed stall, particularly regarding the wake generated by slat brackets and flow separation on the flaps. Validation against Figure 1 demonstrates that FaSTAR consistently achieves the highest level of agreement with reference data and other state-of-the-art solvers. Furthermore, the JAXA experimental data utilized in this study will serve as the global reference for the international community at the 8th AIAA/NASA CFD Drag Prediction Workshop.

Fig.1: Comparison of lift coefficients and sectional pressure distributions across various solvers. FaSTAR results demonstrate high correlation with both numerical reference data and experimental results.

Publications

- Peer-reviewed papers

Markus Zauner, Andrea Sansica, Tomoaki Matsuzaki, Yoimi Kojima, Kosuke Uchida, and Atsushi Hashimoto, "In-Tunnel Delayed Detached-Eddy Simulations and Reynolds-Averaged Navier–Stokes Simulations of the NASA High-Lift Configuration of the Common Research Model", AIAA Journal 2025 63:9, 3700-3718

- Non peer-reviewed papers

[1] Andrea Sansica et al, "Assessment of High-Fidelity Numerical Simulations for the Characterization of CL-max Prediction on the High-Lift Configuration of the NASA CRM Including Wind-Tunnel Walls", NATO-AVT 391, Washington DC, May 2025

[2] Andrea Sansica, Brent W. Pomeroy, Bret Stanford, Daniella Raveh and Hadar Ben-Gida. "DPW-8/AePW-4 Buffet Working Group: An Overview of Mini Workshops 1 and 2," AIAA 2025-3159. AIAA AVIATION FORUM AND ASCEND 2025. July 2025.

- Oral Presentations

[3] Andrea Sansica. "JAXA Contribution to DPW-8/AePW-4 Buffet Working Group for Test Case 2 using FaSTAR," AIAA SCITECH 2026. January 2026

[4] A. Sansica, D.J. Lusher, T. Matsuzaki. Contribution of JAXA to APC-10 using FaSTAR on the CRM high-lift configuration. 第57回流体力学講演会／第43回航空宇宙数値シミュレーション技術シンポジウム (July 2025)

- Other

APC-10 Workshop JAXA-SP-25-005, https://jaxa.repo.nii.ac.jp/records/2002405

Usage of JSS

Computational Information

Process Parallelization Methods: MPI
Thread Parallelization Methods: N/A
Number of Processes: 480 - 2304
Elapsed Time per Case: 200 Hour(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 1.18

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	28936133.63	1.31
TOKI-ST	569455.26	0.59
TOKI-GP	0.00	0.00
TOKI-XM	1949.78	0.67
TOKI-LM	25825.21	1.95
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	19.86	0.06

*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)	2174.92	1.52

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