REYNOLDS-STRESS CLOSURE MODEL FOR CONDITIONAL VARIABLES.

Abstract

Free boundaries of turbulent shear flows show an intermittent character with a sharp interface separating instantaneously turbulent and non-turbulent zones shown by Corrsin and Kistler (1954). Prediction models for turbulent shear flows did not take this intermittent character into account so far. In this paper a second order closure model for turbulent shear flows based on conditional variables (Dopazo 1977) is presented, that allows prediction of intermittency factor, zone-conditioned mean velocities and Reynolds-stresses. It is based on an earlier closure for intermittency factor, mean velocities and kinetic energy and dissipation rate which used the concept of turbulent pseudo-viscosity for the turbulent zone.