The turbulence structure of a highly curved mixing layer

Abstract

As part of a general investigation of complex turbulent flows, extensive one-point measurements have been made of the turbulence structure of the mixing layer bounding a normally impinging plane jet with an irrotational core. The ratio of shear-layer thickness to streamline radius of curvature reaches a maximum of about 0.2, the sense of the curvature being stabilizing. Downstream of the impingement region the shear layer returns asymptotically to being a classical plane mixing layer. The most striking feature of the results is that the return is not monotonic: after decreasing in the region of stabilizing curvature, the Reynolds stresses, triple products, energy dissipation rate and other turbulence quantities overshoot the plane-layer values before finally decreasing. Some conclusions are drawn about the nature of the turbulent transport of Reynolds stress, and about the representation of this and other processes in calculation methods for complex turbulent flows. An incidental result of the work is a comprehensive set of measurements in a plane mixing layer.