NUMERICAL-MODEL FOR CIRCULATION-CONTROL FLOWS

Current computational models for circulation-control flows have been a pplied, in most cases, to elliptical airfoils having only one blowing slot. This work describes a two-dimensional Navier-Stokes solver that has been developed for modeling the flowfields of a circular airfoil w ith two jets. In its original form, the Baldwin-Lomax algebraic turbul ence model is shown to be inadequate for describing compound boundary layers such as those produced by the wall jet. A new turbulence model is therefore proposed. To account for the nonequilibrium production of turbulence at the slot exits and for its suppression due to wall curv ature, two corrections to the turbulence model were implemented. A sla nted slot exit boundary was used to reduce grid skewness without degra ding solution accuracy. The current model has been validated for high- Reynolds-number/low-Mach-number flow over a circular cylinder with two jets. The model is shown to be valid over a wide range of slot flow c onditions including stall. Some insight into wall jet separation is al so presented.