Implementation of the no-slip boundary condition and of a wall shear stress model in the vorticity-velocity exascale-ready Murphy framework

Details

Supervisors

Chatelain, Philippe ; Winckelmans, Grégoire

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil électricien, à finalité spécialisée

Abstract

This master thesis has two main objectives. Firstly, it aims at implementing a no-slip boundary condition. Secondly, it will investigate a wall-modeled LES. The particularity of the 3D solver employed, called Murhpy, is that it exploits the velocity-vorticity formulation of Navier-Stokes. Thus, valid boundary conditions on the velocity and vorticity must be imposed. Before considering these conditions, a Taylor-Green vortex benchmark at Re=1600 is studied to test the code's ability for DNS of turbulent flows. Then, two LES models are implemented, namely the Smagorinsky and Regularized Variational Multiscale models, which will be required for the wall-modeled LES. A no-through flow condition is first added and validated with vortex ring reconnection at Re_Gamma=2000 for the no-slip boundary condition. Then, the latter is implemented by computing a vortex sheet at the wall to nullify the slip velocity and a DNS of channel flow at a low Reynolds number of Re_tau=180 is tested. Finally, the wall-modeled LES is investigated by relaxing the no-slip condition and using a model to impose the wall shear stress from information taken in the log layer tanks to a law of the wall. Since there is no boundary condition on the shear stress, the vorticity at the wall is imposed from the model. Finally, the latter is tested on a turbulent channel flow at Re_tau=2000.