Modeling of turbulence generation at the interface of hybrid turbulence simulation

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K06143
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Fluid engineering
• Research Institution: The University of Tokyo
• Principal Investigator: Hamba Fujihiro 東京大学, 生産技術研究所, 教授 (20251473)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 乱流モデル / RANS / LES / ハイブリッドモデル

Outline of Final Research Achievements

Vortical structures associated with the energy transfer in the scale space were examined to adequately model the turbulence generation at the interface between the RANS and LES regions of hybrid turbulence simulation. A new energy density in the scale space was proposed using the two-point velocity correlation and it was applied to the analysis of the DNS data of turbulent channel flow. As a result, streamwise vortical structures were found which are associated with the inverse energy cascade in the scale space. LES models were examined to sustain the vortical structures and to adequately generate the turbulent fluctuations.

Free Research Field

流体物理学

Academic Significance and Societal Importance of the Research Achievements

自然界や工学分野でよく見られる高レイノルズ数乱流をLESで数値計算する際、壁面近くや上流領域でRANSを用いることが多い。RANSからLESへ切り替わる境界面近くでは乱れ速度の生成を適切に再現する必要がある。単に経験的な関数で乱れを付け加えるのでなく、物理的な機構に基づくモデル式を提案するために、本研究で行われたスケール空間でのエネルギー輸送とそれと伴う渦構造の解析は重要な役割を果たす。