2-D numerical model for predicting the aerodynamic performance of the NOTAR<sup>TM</sup> system tailboom

Current computational models for circulation-control (CC) flows have been applied, in most cases, to ellipse-shaped CC rotor blades having only one blowing slot (i.e., the X-wing). This paper describes the first Navier-Stokes solver which has been developed for modeling the external flowfield of the NOTARTM system tailboom. In its original form, the Baldwin-Lomax algebraic turbulence 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 non-equilibrium production of turbulence at the slot exits and for its suppression due to wall curvature, two corrections to the turbulence model were implemented. A slanted slot exit boundary was used to reduce grid skewness without degrading 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 conditions including stall. Some insight into wall jet separation is also presented.

2-D numerical model for predicting the aerodynamic performance of the NOTAR^TM system tailboom Conference Paper