A Study on the Structure of Turbulent Shear Flow by Numerical Simulation

Abstract

Large-eddy simulation is applied to the numerical investigation of a fully developed wall-bounded turbulent flow at the Reynolds number of 11500 with 32×32×32 grid points. Through the observation of the distribution of vorticities, production of Reynolds stress and turbulent kinetic energy, which are difficult to obtain experimentally, the structure of the turbulence is discussed. High speed flow towards the wall and lift-up of a low speed fluid are shown to have a tendency to develop into so-called sweep and ejection. Where these events happen contiguously, high and low speed streaks of streamwise vorticity are observed, which are regarded as the center of the production of turbulence. Well known counter-rotating streamwise vortices are appropriate as the conditionally averaged statistics, but they are not observed as an instantaneous structure in the flow field.