Numerical Simulations of Fully Developed Turbulence

JAXA Supercomputer System Annual Report February 2025-January 2026

Report Number: R25EACA05

Subject Category: JSS Inter-University Research

Responsible Representative: Susumu Goto, Professor, Osaka University
Contact Information: Susumu Goto(s.goto.es@osaka-u.ac.jp)
Members: Keisuke Endo, Susumu Goto, Ryusuke Inoue, Yusuke Koide, Ippei Kato, Yuya Kanosue, Yutaro Motoori, Satoshi Matsumoto, Hayato Masuda, Kentaro Nakajima, Nozomu Osaka, Keita Okubo, Kaishin Shioyama, Masahiro Suzuki, Toshizo Terai, Kentaro Tanaka, Daiki Watanabe, Naoki Yuguchi

Abstract

Most flows around us are turbulent, and their prediction and control are important in a wide range of fields. Fortunately, with the advancement of supercomputers, the Reynolds numbers of turbulence that can be simulated numerically have been increasing year by year. However, it is still impossible to simulate, without modeling, the extremely high Reynolds number turbulence encountered in aerospace engineering. Therefore, for many years, researchers have sought to develop turbulence models based on the universality of the small-scale statistics and dynamics of turbulence. In the present study, through numerical simulations of turbulence under various boundary conditions, we aim to clarify the origin of the universality of turbulence and, by also elucidating the sustaining mechanisms of turbulence in complex fluids, to construct a new turbulence model.

Reference URL

N/A

Reasons and benefits of using JAXA Supercomputer System

Many of the flows that appear in aerospace engineering are fully developed turbulence at high Reynolds numbers, and understanding their dynamics and statistics is directly related to various projects in JAXA. In particular, if the construction of a new turbulence model, that is the main research aim of the present project, is successful, it should support the foundation of numerical simulations for many projects.

Achievements of the Year

Our series of previous studies has made it clear that understanding the dynamics of coherent vortices in turbulence is essential for constructing turbulence models. Therefore, in this fiscal year, we devoted particular effort to research aimed at clarifying the sustaining mechanism of turbulence in non-Newtonian fluids, which do not obey Newton's constitutive law. In this study, we conducted a systematic investigation using direct numerical simulations of turbulence together with Brownian dynamics simulations of polymers. As a result, we showed that polymers suppress vortices whose rotation periods are shorter than the relaxation time of the polymers.

Fig.1: Direct numerical simulations of turbulence under periodic boundary conditions in (left) a Newtonian fluid and (right) a non-Newtonian fluid. The addition of polymers suppresses small-scale vortices.

Publications

- Peer-reviewed papers

1. Satoshi Matsumoto, Masanobu Inubushi, Susumu Goto, Data-driven closure model for large-scale eddies in the energy-containing range of turbulence, in press.

2. Yutaro Motoori, Susumu Goto, Enhancement of wall-bounded turbulence by solid particles under gravity, Int. J. Heat Fluid Flow, 116 (2025) 109933.

3. Yutaro Motoori, Susumu Goto, Attenuation mechanism of wall-bounded turbulence by heavy finite-size particles, J. Fluid Mech., 1014 (2025) A30.

4. Daiki Watanabe, Susumu Goto, Convection cells in a partially filled horizontal rotating cylinder: Effect of an axial flow, Phys. Rev. Fluids, 10 (2025) 063902.

5. Yusuke Koide, Susumu Goto, Relationship between the power spectral density of the Lagrangian velocity and the hierarchy of coherent vortices in turbulence, Phys. Rev. Fluids, 10 (2025) 054609.

6. Awai Hideto, Yutaro Motoori, Susumu Goto, Attenuation of turbulence in a periodic cube by anisotropic solid particles, J. Fluid Mech., 1008 (2025) A6.

Usage of JSS

Computational Information

Process Parallelization Methods: MPI
Thread Parallelization Methods: OpenMP
Number of Processes: 64 - 128
Elapsed Time per Case: 30 Hour(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 0.08

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	926472.92	0.04
TOKI-ST	178223.23	0.18
TOKI-GP	196.57	0.00
TOKI-XM	6304.48	2.17
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	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	0.00	0.00

*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.