Decomposition and control of the mean skin-friction drag in wall-bounded turbulent flows
The mean skin-friction drag contributes to the total drag up to 50 % for commercial aircrafts, 90 % for submarines and almost 100 % for long pipe and channel flows. Understanding the mean skin-friction drag generation and its associated near-wall dynamical system is of fundamental and practical importance, particularly for the evaluation of aerodynamic/hydrodynamic performance and design of drag reduction approaches. With a novel method (Renard &Deck, J. Fluid Mech. 790, 2016; Li. et al. J. Fluid Mech. 875, 2019), we decomposed the mean friction drag into three physics-informed contributions. The Reynolds number effects, compressibility effect, and adverse-pressure-gradients effects on the scaling of each contributing term are investigated. On the other hand, controlling of the mean friction drag with riblets and mass suction or blowing will be discussed to provide some hints to develop modern drag reduction approaches.
Speaker: Prof. Weipeng LI
Zoom Link: https://hkust.zoom.us/j/94469128948?pwd=c1BOY1JjSlg1SmNleERKeGVwOTNhdz09
Meeting ID: 944 6912 8948
Passcode: 051628
Weipeng Li, an associate professor in School of Aeronaustics and Astronautics, Shanghai jiaotong University (SJTU). Prof. Li got his Ph.D degree from the University of Tokyo, and joined SJTU since 2012. His research interests span the areas of wall turbulence and aero-acoustics. A common thread of his research is to understand the dynamics of turbulence and its relation with the turbulent friction drag and noise generation. Special attention is paid to the drag reduction and noise control in aerospace engineering. Broadly speaking, his research belongs to the area of Aircraft Design, which aims to develop modern aircrafts with low-drag and low-noise.