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# 세미나 제목: Predictive and Affordable Simulation of Wall-Bounded Turbulent Flows

# 일시: 2024년 8월 23일 (금) 12:00~ 

# 장소: #102호 강의실

# 언어 : English

# 호스트: Prof Jee, Solkeun 

# 초록:

Predictive and affordable simulation of wall-bounded turbulent flows remains as a pacing item in CFD, and significant progress has been made over the past decade in near-wall models for large-eddy simulation (LES) to this end. In this talk, I will first discuss the grid-resolution requirement in the scale-resolving simulation of turbulent flows, and how the presence of walls renders this scale landscape more complicated and in the context of LES. Wall modeling will be introduced as a remedy to bypass the computationally demanding inner portion of the boundary layer, by modeling the momentum transport in the near wall region rather than resolving it. Such wall-modeled LES (WMLES) approaches result in significant savings in the computational cost as compared to the wall-resolved approaches, where the reduction in the cost is proportional to the Reynolds number. The concept of wall modeling will be further expounded from discussion of the state-of-the-art wall models with varying degrees of complexity and physical accountability of nonequilibrium effects. Application of widely used wall models to nonequilibrium turbulent boundary layers will be showcases, including atmospheric surface layer developing over a New Mexico sand dunes and boundary layers subject to successive application of favorable and adverse pressure gradients, with and without mean flow three dimensionality which leads to formation of complex skewed mean velocity profiles. Time permitting, the issue of grid convergence in the inherently underresolved WMLES will be discussed.

#Speaker bio:

George Park is an Assistant Professor of Mechanical Engineering and Applied Mechanics at the University of Pennsylvania. He received his Ph.D. and M.S. in Mechanical Engineering (ME) from Stanford University in 2014 and 2011, respectively, and his B.S. in ME from Seoul National University, South Korea, in 2009. He worked as a postdoctoral fellow and an engineering research associate at the Center for Turbulence Research (Stanford) prior to joining UPenn as a faculty member. His research interests include high-fidelity numerical simulation of complex wall-bounded turbulent flows, computational methods with unstructured grids, non-equilibrium turbulent boundary layers, and fluid-structure interaction.