CALCULATION OF FLOWS CHARACTERIZED BY EXTENSIVE CROSS FLOW SEPARATION

摘要

Flows with extensive cross flow separation appear in many flight vehicle configurations. Traditionally these types of flows are difficult to simulate accurately, especially if the separation is extensive (flow at high incidence or strong swept shock waves impinging on boundary layers). The present author has shown in previous publications that if the 3-D structure of these flows is considered for modifying a conventional turbulence model, the efficiency of the model is enhanced considerably. This concept has been demonstrated for the case of the supersonic fin/plate interaction, and it is based on the observation that in turbulent flows characterized by extensive cross-flow separation, a layer of low-turbulence exists close to the surface (underneath the core of the separation vortex). This flow feature has been incorporated in the Balwin-Lomax algebraic turbulence model by the introduction of a new relation for the calculation of the eddy viscosity within the separation domain. In the present paper the modified turbulence model is extended for application to more complicated shock wave/turbulent boundary layer interactions (crossing shocks) and to high-angle-of-attack flows.