Research on laminar fins system

JAXA Supercomputer System Annual Report February 2025-January 2026

Report Number: R25EA0601

Subject Category: Aeronautical Technology

Responsible Representative: Dongyoun Kwak, Hub Maneger, Aviation Environmental Sustainability Innovation Hub/Aviation Technology Directorate
Contact Information: Naoko Tokugawa(tokugawa.naoko@jaxa.jp)
Members: Xavier Chanteux, Naomasa Ikegami, Takahiro Ishida, Fumitake Kuroda, Keisuke Ohira, Naoko Tokugawa, Kaito Tamazaki, Keiji Ueshima, So Yamamoto, Hayahide Yoshida

Abstract

With the aim of supporting the development of next-generation aircraft with improved environmental performance, this study seeks to enhance the technology readiness of laminar flow design, boundary-layer control through surface cooling, and riblet technologies that enable the reduction of aircraft drag (skin-friction drag). Furthermore, laminar-flow wing design technologies, including shock-wave control, will be further advanced.

Reference URL

Please refer to https://www.aero.jaxa.jp/eng/research/ecat/igreen/ .

Reasons and benefits of using JAXA Supercomputer System

For laminar flow technologies intended to reduce aircraft fuel consumption, a large number of high-fidelity computational fluid dynamics (CFD) analyses are required to accurately capture fine-scale boundary-layer flows. In particular, CFD simulations using supercomputers are essential for project implementation, including the evaluation of boundary-layer transition induced by inflow disturbances and the assessment of boundary-layer control effectiveness.

Achievements of the Year

As a follow-up to the design and validation technologies for a laminar vertical tail, we validated the prediction of transition locations on a laminar vertical tail using a transition model coupled with Reynolds-averaged Navier–Stokes (RANS) equations.The analyses were conducted using the unstructured-grid CFD solver FaSTAR, in which the Langtry–Menter (LM2015) model was employed as the transition model. In simulations where the surface roughness input parameter for the transition model was set to the actual value of 0.05 micron, the predicted transition locations were in good agreement with wind tunnel test results for both cases with Reynolds numbers (based on chord length) of 12.8 and 23.6 million.

Fig.1: Comparison of transition prediction locations obtained using the LM2015 model with a roughness height of 0.05 micron and wind tunnel test results

Publications

- Oral Presentations

Keiji Ueshima, Takahiro Ishida, Keisuke Ohira, Naoko Tokugawa, 63th Aircraft Symposium, "Transition prediction of NLF vertical tail with transition model"

Usage of JSS

Computational Information

Process Parallelization Methods: MPI
Thread Parallelization Methods: Automatic Parallelization
Number of Processes: 48 - 9600
Elapsed Time per Case: 12 Hour(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 0.98

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	24035870.76	1.09
TOKI-ST	64741.56	0.07
TOKI-GP	1127.50	0.02
TOKI-XM	38800.37	13.33
TOKI-LM	12063.18	0.91
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	51200.00	0.34
/ssd	0.00	0.00

Archiver Resources
Archiver Name	Storage Used (TiB)	Fraction of Usage*2(%)
J-SPACE	38.60	0.12

*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)	1655.09	1.16

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