Department of Nuclear and Atomic Physics Seminars

Large-Eddy Simulation of Flow Past a Circular Cylinder and Airfoils

by Prof. Ravi Samtaney (Professor, Mechanical Engineering and Acting Dean,Physical Science and Engineering King Abdullah University of Science and Technology (KAUST), Saudi Arabia)

Wednesday, December 19, 2018 from to (Asia/Kolkata)
at TIFR, Mumbai ( AG - 69 )
Description
A canonical flow in fluid mechanics is flow past a circular cylinder. At about Reynolds number ~ 300,000 a curious phenomenon is observed: this is the drag crisis. We report recent progress on wall-resolved large-eddy simulation (LES) of flow past a circular cylinder. Three configurations are considered: a smooth cylinder, a grooved cylinder and a rotating cylinder. An examination of the local skin friction and flow separation details indicates that the drag crisis is not necessarily attributed to the transition from laminar to turbulent of the boundary layer. The sub-grid-scale (SGS) model employed is the stretched spiral vortex SGS model, originally proposed by Misra & Pullin (Phys. Fluids 1997). In addition, we discuss recent results of wall-modeled LES of flow past airfoils with an emphasis on the strong validation against experiments. The wall model is essential to avoid resolving the flow at the wall and involves the derivation of a Dirichlet boundary condition for the velocity at a virtual wall.