Turbulence characteristics of wall jets along strong convex surfaces

Abstract

Mean flow and turbulence characteristics of two-dimensional wall jets along strong convex surfaces are investigated in an experimental manner. Distributions of mean velocities, Reynolds normal and shear stresses and dissipation across the wall jets are measured, then the balances of advection, production and dissipation in the Reynolds stress equations are examined. The jet spreading and the levels of the Reynolds stresses of the strong convex wall jets increase significantly as the wall jets develop along the surfaces. These trends are well correlated with a curvature parameter represented by the ratio of half-width to surface curvature. The magnitudes of the terms in the Reynolds stress equations for the strong convex wall jet are increased significantly compared with those of the plane wall jet. In particular, these appear to be strong centrifugal effects on the production of the turbulent fluctuation normal to the surface. This production, coupled with the production of the shear stress and the advection of streamwise turbulent fluctuation, increase the interactions of mean flow and turbulence.