Coherent structures from the linearized Navier-Stokes equations for wall-bounded turbulent flows

Abstract

In this dissertation we present a study of the large-scale coherent structures that are modelled by the linearized Navier-Stokes equations in a turbulent channel flow. The results presented here are divided into three parts: i) a study of the wall-normal coherence of these large-scale structures, ii) estimation of the instantaneous and the statistical features of these structures and iii) an analysis of the effect of stratification on the structures. In all three cases the trends obtained from the linear model are compared to Direct Numerical Simulation (DNS) datasets. In the first part, the wall-normal extent of the large-scale structures modelled by the linearized Navier-Stokes equations..