REYNOLDS STRESS CLOSURE APPLIED TO AXISYMMETRICAL, IMPINGING TURBULENT JETS

A second-order, single-point closure model for calculating the transpo rt of momentum in turbulent flows is extended to cover flows that are close to solid surfaces. In such flows the proximity of a solid bounda ry directly influences the fluctuating pressure field within the main body of the now and leads to a dampening of velocity fluctuations norm al to the wall. These effects are accommodated through the incorporati on of an additional contribution in the modelled form of the redistrib utive fluctuating pressure term used in the Reynolds stress transport equation. Predictions of the extended closure model are compared with available data in configurations where an air jet impinges orthogonall y onto a plane surface. The inclusion of the wall reflection model is shown to result in superior predictions of mean velocities, and normal and shear stresses. In particular, normal-to-wall velocity fluctuatio ns and shear stresses are successfully damped resulting in agreement w ith observations.