Validation of a new k-epsilon model with the pressure diffusion effects in separated flows

Abstract

The contribution of the "rapid" part of the pressure diffusion to the turbulent kinetic energy balance is analyzed, and a new model to describe its effect is suggested. A new transport equation for the turbulent kinetic energy is derived. The new k-equation does not require any modification in the standard epsilon-equation. A new k-epsilon model, which includes the new k-equation and the standard epsilon-equation, is validated in four separated flows: a planar diffuser, over a backstep, in a channel with wavy walls, and in an axisymmetric combustion chamber. It is shown that a new model reproduces the mean velocity, shear stress, and turbulent kinetic energy profiles and the skin friction coefficient in very good agreement with experimental data.