本文へ移動

サイトナビゲーションへ移動

検索ボックスへ移動

サイドバーへ移動

ここは、本文エリアの先頭です。

Study of complessibility effect on low Reynolds number flow over a plate

JAXA Supercomputer System Annual Report February 2022-January 2023

Report Number: R22EACA49

Subject Category: JSS Inter-University Research

PDF available here

  • Responsible Representative: Taku Nonomura, Associate Professor, Tohoku University
  • Contact Information: Taku Nonomura, Tohoku University(nonomura@tohoku.ac.jp)
  • Members: Taku Nonomura, Takayuki Nagata

Abstract

Large-eddy simulations (LES) of the compressible flow around the plate with Reynolds number O (10^3) -O (10^4) were performed. The compressibility effects on the laminar flow separation bubble formed around the leading edge of the flat plate and turbulent transition were investigated. The flat plate is one of the basic shapes the same as a sphere and cylinder. Under the incompressible flow condition, the formation of laminar flow separation bubbles and the turbulent transition of the boundary layer occurs in the Reynolds number region investigated in this study. These are important phenomena for the understanding of the low Reynolds number flows. In this study, we will investigate the effect of compressibility on them in detail.

Reference URL

N/A

Reasons and benefits of using JAXA Supercomputer System

In the present study, a parametric study by large-eddy simulations is conducted, and thus, a large-scale parallel calculation is required.

Achievements of the Year

We calculated the flowfield at the Reynolds numbers between 5000-15000 and the Mach numbers between 0.2-0.9. Figures 1 and 2 show the flow visualization at the Reynolds numbers 20,000 and 11,000, respectively. The isosurface is the second invariant of the velocity gradient tensor, and the isosurface and contour are colored by the streamwise velocity distribution normalized by the freestream velocity. For high Mach number conditions, the laminar flow separation bubble formed at the leading edge is longer, and the turbulent transition is significantly delayed. The laminalization occurs in lower Mach number conditions for the Reynolds number of 11,000. The similarity in the stabilization effect due to the decrease in the Reynolds number and increase in the Mach number was found.

Annual Reoprt Figures for 2022

Fig.1: Mach number effects on the vortex structure and streamwise velocity field at the Reynolds number of 20,000

 

Annual Reoprt Figures for 2022

Fig.2: Mach number effects on the vortex structure and streamwise velocity field at the Reynolds number of 11,000

 

Publications

– Poster Presentations

Takayuki Nagata and Taku Nonomura “Implicit large-eddy simulation of subsonic compressible low Reynolds number flow over a flat plate at Re = 20,000,” 75th Annual Meeting of the Division of Fluid Dynamics, S01.00090, Indianapolis, USA, 2022

Usage of JSS

Computational Information

  • Process Parallelization Methods: MPI
  • Thread Parallelization Methods: OpenMP
  • Number of Processes: 60
  • Elapsed Time per Case: 130 Hour(s)

JSS3 Resources Used

 

Fraction of Usage in Total Resources*1(%): 0.02

 

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 653223.93 0.03
TOKI-ST 0.00 0.00
TOKI-GP 0.00 0.00
TOKI-XM 0.00 0.00
TOKI-LM 0.00 0.00
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 58.06 0.05
/data and /data2 113493.33 0.88
/ssd 36.11 0.01

 

Archiver Resources
Archiver Name Storage Used
(TiB)
Fraction of Usage*2(%)
J-SPACE 32.90 0.15

*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)
0.00 0.00

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

JAXA Supercomputer System Annual Report February 2022-January 2023