Calculation of Planc-of-Symmetry Boundary Layers with a Modified K- Model

Abstract

The effects of vortex stretching and normal stresses on the development of turbulent boundary layers are numerically investigated by adopting both the vortex stretching invariant and the preferential normal stress concept in the dissipation equation of the standard k-epsilon. An application of the proposed epsilon-equation to a plane-of-symmetry boundary-layer flow reveals that the preferential normal stress terms under the flow convergence reduces the turbulent kinetic energy k and the eddy viscosity nu-t, whereas the squeezing of vorticity augments them, consistent with experimental observation. Comparison of predicted profiles of various flow variables by the proposed model with those by other k-epsilon and mixing length models demonstrates that the present epsilon-equation improves markedly the computational accuracy of the relatively complex flow in a plane of symmetry.