Turbulence Attenuation by Small Particles in Simple Shear Flows

Abstract

This paper is concerned with the influence of a dispersed phase on carrier flow turbulence. The carrier flow is assumed to be a simple homogeneous shear, in which the fluid Reynolds stress tensor is independent of spatial location, but in which there is a linear mean shear across the flow. In the shear flow, the Reynolds stress is nondiagonal, and we find extra dissipation terms in the Reynolds stress equations compared with those arising in isotropic turbulence. The source terms are used to develop a simple model to predict changes in turbulence levels in particle-laden shear flows. It is shown that the general effect of particles is to attenuate turbulence. The resulting expression is not explicitly dependent on the shear. The theory is used to predict turbulence attenuation in near-homogeneous particle-laden flows in pipes and channels and is compared with experimental data. [S0098-2202(00)00401-6]