A Reynolds-stress closure model of turbulence applied to the calculation of a highly curved mixing layer

Abstract

The measurements in a highly curved mixing layer reported by Castro & Bradshaw (1976) are used to evaluate the performance of a calculation method based on the solution of modelled transport equations for the Reynolds stresses and the dissipation rate of turbulent energy. The model reproduces the suppression of turbulence by stabilizing curvature and, downstream of the curved region, where the flow returns asymptotically to being a plane mixing layer, calculated values of turbulent intensity and shear stress overshoot the plane-layer values in accordance with the experimental observations. The results are compared with those obtained by Townsend (1980) from a rapid-distortion model which correctly predicts the streamwise variation of the shear stress to intensity ratio. By contrast, calculations based on a conventional two-equation eddy-viscosity model fail badly to account for curvature effects on this flow.