Numerical solutions of turbulent boundary layer equations and calculation of turbulence intensities and turbulence shear stresses in incompressible flow on convex wall

The structure of the turbulent boundary layer along a convex wall was studied using numerical solutions of boundary layer equations on curved surface. Turbulence intensities and turbulent shear stress were calculated in the mentioned case. Both sets of results were compared with those obtained from a fully developed flat-wall boundary layer. The results clearly show that convex curvature strongly attenuates most of the organized large-scale structures in the flow and these structures are not restored to their earlier state quickly after the removal of streamline curvature. It was concluded that for the boundary layer on convex surfaces the stabilizing effects lead to decreased turbulent momentum exchange between fluid particles similar to the way convex curvature causes flow to be stabilized. Results show that the effect of convex curvature is to nearly arrest the growth of boundary layer thickness. In this case the model used to calculate turbulent parameters is an improvement over Low Reynolds Number (LRN) turbulence models. It is modified by both wall functions and curvature parameters for curved surfaces.

کلیدواژه ها:

LRN turbulence model ، Boundary layer equations ، Shear stress ، Turbulence intensities ، Convex curvature