Large-scale Turbulence Structures in a Manipulated Channel Flow

Abstract

Large-eddy simulation (LES) is a proper means to show the effect of large-edd breakup devices (LEBUs) on turbulence structures in a high Reynolds number channel flow. Three different types of simulations are performed on the basis of the filtered Navier- Stokes equations: 1) a LES of fully developed channel flow with periodicity boundary conditions (PBC) in order to generate inflow boundary conditions, 2) a LES of the same flow using inflow/outflow boundary conditions (IOBCs) with the aim of testing their influence and 3) a LES of manipulated channel flow (MCF) with inflow boundary conditions from 1). Characteristics of the numerical method are a leapfrog-scheme for time integration and the capacitance matrix technique to solve the Poisson equation for the pressure. Results for a 64×32×32 grid are presented. They clearly exhibit the effect of breakup of large scale instantaneous structures and of decrease of turbulence intensities and Reynolds stress due to the primary plate effect.