Estimation of turbulent dissipation rate using 2D data in channel flows

Abstract

The dissipation rate of turbulent kinetic energy is a key parameter in the analysis of turbulent flows and its accurate determination in experiments is of paramount importance to turbulence research. In order to calculate turbulence dissipation rate, values of all the components of fluctuating velocity gradient tensor are required. Experimental methods, in particular 2D planar Particle Image Velocimetry (PIV), cannot measure velocity components in all three spatial dimensions, hence dissipation cannot be calculated completely from the data provided by such methods. This paper uses data from a Direct Numerical Simulation (DNS) to compare the true turbulent dissipation in a channel flow with its estimates calculated from various models available in literature. These models are shown to fail near the wall, where a substantial fraction of the turbulent kinetic energy is dissipated, significantly limiting estimates of total turbulent dissipation in the flow. This study aims to develop an improved model to estimate turbulent dissipation rate where information limited velocity field information is available especially in the near wall region.