Tangential fuselage blowing on an ogive cylinder

The nose vortices of aircraft or missiles tend to become asymmetric at high angles of attack producing a side force which is destabilizing to the body. A jet located near the nose and blown tangentially to the fuselage has the ability to alter the flow field and diminish the unwanted side force. Alternatively, it can produce a large side force which can be used for improving the maneuverability of the vehicle.;This work explores the effects of tangential blowing on the vortical structures that develop about the fuselage of a missile or aircraft at a high angle of attack. A tangent-ogive cylinder configuration was used to allow comparison with experiments. The study was carried out numerically by solving the Thin-Layer, Reynolds-Averaged, compressible Navier-Stokes equations. A zonal method was used to solve the equations. The jet was implemented with an actuator plane. Computations were conducted in a fully laminar and a fully turbulent manner. Appropriate algebraic turbulence models were used for the jet and the boundary layers in the turbulent computations. The study was conducted at a Reynolds number, based on diameter, of 52000, and Mach number of 0.2. The angles of attack used were 10, 30 and 45 deg. The influence of slot location were also explored.;This study confirmed that large side forces could be generated from tangential blowing even at low angles of attack. Several conclusions were made concerning the physical mechanisms by which the jet interacts with the ambient flow field to produce a side force: (1) A pressure gradient normal to the surface is created near the wall due to the momentum of the jet being forced to follow the curvature of the surface. (2) A large amount of vorticity is added to the flow field by the jet. In the region of the slot, the vorticity has the effect of inducing circulation around the body. Downstream of the slot, the vorticity alters the strength of the nose vortices. And (3), the position of the nose vortices can be altered by the actions of the jet.