Unsteady, nonequilibrium turbulence in high Reynolds and high Mach number regime and its applications

2021 Fiscal Year Final Research Report

• Project/Area Number: 18H01367
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 19010:Fluid engineering-related
• Research Institution: Nagoya University
• Principal Investigator: Nagata Koji 名古屋大学, 工学研究科, 教授 (50274501)
• Co-Investigator(Kenkyū-buntansha): 渡邉 智昭 名古屋大学, 工学研究科, 准教授 (70772292)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 乱流 / 風洞実験 / 数値計算

Outline of Final Research Achievements

In recent years, the existence of nonequilibrium turbulence (or non-Kolmogorov turbulence) is unveiled, in which the energy flux and dissipation of turbulent kinetic energy are not balanced. However, it is not yet clear whether or not such kind of unsteady turbulence appears even at high or extremely low Reynolds numbers or high Mach number regime. In addition, it is not clear whether nonequilibrium phenomena are observed in various types of turbulent flows. The purpose of this study is to investigate in detail the turbulent energy generation and dissipation mechanism in various types of turbulent flows, including high Reynolds and extremely low Reynolds numbers and high Mach number regimes, and to clarify the nonequilibrium characteristics of such turbulent flows.

Free Research Field

流体力学

Academic Significance and Societal Importance of the Research Achievements

乱流の生成と散逸機構を明らかにすることは流体力学に関する基礎研究として重要であるのみならず，市販の数値計算コードで用いられている乱流モデルの評価と改良という観点から実用上も重要な課題である．本研究では，新たに開発した動的格子を用いた風洞実験を始め，乱流の直接数値計算とラージエディシミュレーションも併用することで，高レイノルズ数・高マッハ数域を含む様々な乱流場における非平衡性を明らかにしたものであり，特に当該分野の学術的進展に大きく寄与するものである．