JAXA Supercomputer System Annual Report February 2021-January 2022

Report Number: R21EACA13

Subject Category: JSS Inter-University Research

PDF available here

• Responsible Representative: Kazuo Matsuura, Associate Professor, Ehime University, Graduate School of Science and Engineering
• Contact Information: Kazuo Matsuura(matsuura.kazuo.mm@ehime-u.ac.jp)
• Members: Kazuo Matsuura, Kazuto Takimoto

Abstract

In hypersonic transitional flows, there are many complicated factors such as density fluctuation and temperature fluctuation due to the co-existence of the region slower than the speed of sound and the region faster than the speed of sound inside the boundary layer. Detailed investigations into the vortex dynamics occurring inside the boundary layers are expected. In this study, we aim to clarify the nonlinear vortex dynamics especially in the late-stage by conducting direct numerical simulations of laminar-turbulent transition in compressible boundary layers observed in hypersonic flows. Also, we develop a mathematical methodology to directly introduce vortices responsible for the late stage to the boundary layers, and its computational methods.

Reference URL

N/A

Reasons and benefits of using JAXA Supercomputer System

For the investigation of boundary layer transition of hypersonic flows, numerical simulation is a central tool because measurement is difficult due to the existence of acoustical disturbance in a wind tunnel. Because boundary layer transition is susceptible to disturbance, and in addition transition is hard to occur due to strong compressibility, powerful supercomputers that enable high-accuracy large-scale computation are necessary to get results in a short time period.

Achievements of the Year

Ring tone is a kind of feedback sound emitted from a system in which pressure waves generated when vortices from a nozzle collide with a downstream obstacle, propagate upstream, and regulate the timing of further vortex ejection from the nozzle. This year, we placed a ring downstream of the subsonic jet and clarified the mechanism of ring tone generation. Figure 1 shows how volumetric vortical regions interact with the ring.

Fig.1: Interaction with volumetric vortical regions and the ring

Publications

- Peer-reviewed papers

1. K. Matsuura, K. Mukai, M.A. Langthjem,

"Computational and experimental study on ring tone,"

WIT Transactions on Engineering Sciences, Vol. 132, pp. 141-151 (2021).

2. K. Matsuura,

"Numerical evaluation of the regions of high energy dissipation for different free-stream turbulence in transitional low-pressure turbine flows,"

Proc. of the 15th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, pp. 1538-1543.

3. Kazuo Matsuura, Yasuhide Fukumoto,

"Hierarchical Clustering Method of Volumetric Vortical Regions with Application to the Late-Stage of Laminar-Turbulent Transition,"

Physical Review Fluids, pp.1-32 (2022) (accepted).

Usage of JSS

Computational Information

• Process Parallelization Methods: MPI
• Thread Parallelization Methods: Automatic Parallelization
• Number of Processes: 16 - 64
• Elapsed Time per Case: 168 Hour(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 0.01

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 2021-January 2022