JAXA Supercomputer System Annual Report February 2025-January 2026

Report Number: R25EACA26

Subject Category: JSS Inter-University Research

PDF (to be added)

• Responsible Representative: Takuto Ogawa, Project assistant professor, Shibaura Institute of Technology
• Contact Information: Takuto Ogawa(ogawa-t@shibaura-it.ac.jp)
• Members: Takuto Ogawa

Abstract

The project develops flow control technic by using dielectric barrier discharge (DBD) plasma actuator to establish high efficient and robust vehicle systems such as rockets, aircrafts, and motor vehicles. We propose and demonstrate separation control methods to adapt unsteady flows over the airfoils through a series of high-fidelity unsteady simulations.

Reference URL

N/A

Reasons and benefits of using JAXA Supercomputer System

To conduct the large eddy simulations using the LANS3D as a computational solver.

Achievements of the Year

We conducted high-fidelity large eddy simulations to control flow separation around a NACA 0015 airfoil using a DBD plasma actuator (PA), and performed a more detailed verification of the transition control model (Ref.: Peer-reviewed paper #1), which has demonstrated a certain degree of control effectiveness in this project up to last fiscal year. The verified transition control model demonstrates that by introducing periodic fluctuations into the laminar boundary layer distributed near the leading edge of the airfoil, these fluctuations are maintained in a spatially and temporally stable manner within the laminar boundary layer. This suggests that by installing the PA upstream of the transition point and setting the periodic drive (burst drive) of the PA to a relatively high frequency, vortex structures effective for large-scale separation control can be stably generated. In this study, we verified the effectiveness of this control model in the flow around a NACA0015 airfoil at an angle of attack of 16 degrees and a Reynolds number of Re = 63,000. Based on this transition control model, the PA installation position was determined to be 5% upstream of the transition point, and the PA burst drive frequency was set to F+ = 20. This burst drive frequency is relatively higher than the effective values generally discussed to date (such as F+ = 6 or 10). Numerical calculations showed that in the case of F+ = 20, large-scale separation could be stably suppressed both temporally and spatially. Furthermore, suppression of separation resulted in a lift-to-drag ratio exceeding 15, representing an improvement of approximately fivefold compared to the uncontrolled case. On the other hand, in cases with lower burst drive frequencies (F+ = 5 and 10), large-scale separation could not be sufficiently suppressed. Based on the above, the proposed transition control model was confirmed to be effective to a certain extent.

Publications

- Peer-reviewed papers

Takuto Ogawa, Aiko Yakeno, Kozo, Fujii, "Transition Control for Separated Flow over Airfoil by Periodic Body Forcing", Proceedings of the 10th IUTAM Symposium on Laminar-Turbulent Transition, pp. 15-20, Jan. 2026.

- Invited Presentations

Takuto Ogawa, "Turbulence in Compressible Fluids and Its Active and Passive Control", IMI Shared Use and Short-Term Joint Research Program, Kyushu University, Nov. 2025.

Usage of JSS

Computational Information

• Process Parallelization Methods: MPI
• Thread Parallelization Methods: OpenMP
• Number of Processes: 80
• Elapsed Time per Case: 20 Hour(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 0.00

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 2025-January 2026