Description of turbulent events through the analysis of POD modes in numerically simulated turbulent channel flow

Abstract

The flow of a viscous incompressible fluid in a plane channel is simulated numerically with the use of a parallel computational code for the numerical integration of the Navier-Stokes equations. The numerical method is based on a mixed spectral-finite difference algorithm and the approach of the Direct Numerical Simulation (DNS) is followed in the calculations. A turbulent-flow database is constructed, including 500 non-dimensional time steps of the turbulent statistically steady state flow field at Reynolds number Re τ = 180. The coherent structures of turbulence are extracted from the fluctuating portion of the velocity field with the use of the Proper Orthogonal Decomposition technique (POD). Turbulent events occurring in the flow are described in terms of temporal dynamics of the coherent turbulent structures, the flow modes educed with the POD technique. © Springer-Verlag Berlin Heidelberg 2005.