Near-wall boundary condition for LES

Abstract

This study concerns with the new technique of enforcement of boundary conditions for LES in near wall region. The new approximate boundary condition which have been proposed is termed as Robin type boundary condition. For the purpose of transferring the boundary conditions to an intermediate location near the wall, the complete domain has been demarcated into two sub domains; the inner domain and outer domain. This process of demarcation exhibits the common interface where Robin type boundary condition can be applied. It has been observed that the location at which Robin type boundary condition has been placed is insensitive to the outer domain solution.The simulations are one dimensional and time dependent. An in-house code has been developed for this purpose. Different time step sizes and simulation times have been considered. The numerical scheme used is the Crank-Nicolson scheme which is second order accurate in space and time. The initial data employed is linear in nature. Results from the decomposed domain have been compared with the benchmark solutions of the single domain; the results obtained by implementing the Robin type boundary condition are found to be in very good agreement with the benchmark solution. Furthermore, artificial perturbations have been introduced into the initial data profile as to represent the unsteadiness of turbulent flow. In this case, the domain decomposed solutions obtained by implementing Robin type boundary condition coincide with the perturbed benchmark solution and provide encouraging results.

Date of Award	31 Dec 2011
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Sergey Utyuzhnikov (Supervisor)