Transient growth study of quasi-coherent structure of non-equilibrium turbulence for sophisticated flow control

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K21677
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Fluid engineering; Thermal engineering
• Research Institution: Tohoku University (2017); Japan Agency for Marine-Earth Science and Technology (2016); Japan Aerospace EXploration Agency (2015)
• Principal Investigator: Yakeno Aiko 東北大学, 流体科学研究所, 助教 (30634331)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 流体制御 / 安定性解析 / 壁乱流 / 過渡成長 / 剥離制御 / 摩擦抵抗低減制御 / ストリーク / 縦渦構造

Outline of Final Research Achievements

This research is targeting flow field in an oscillating channel or around a two-dimensional hill. That is non-equilibrium turbulent under acceleration and deceleration of the mainstream, in which turbulence production and dissipation are not balanced. We studied a mechanism to explain and control turbulence coherent structure such as low speed streak and streamwise vortex generated near the wall surface. In particular, we developed a program code to compute transient growth of non-modal stability of the flow, and analyzed the stability on the base flow that changed in spatiotemporal. Turbulence structure by direct numerical simulation was compared with that by the linear analysis and we obtained useful knowledge for constructing a smart flow control strategy.

Free Research Field

流体工学