Vortex Flow Structure over the Nose of Aircraft

Using time-dependent compressible Navier-Stokes equations with finite volume incorporating a third-order-accurate discretization scheme,flow structure over the nose of aircraft is simulated,and different types of vortex series are described clearly.The result shows that,at lower angles of attack,the topological combination type of saddle and node on the surface of the nose develops to different spatial vortex series at the nose of the aircraft.Horn vortices are developed from the stabilized spiral point.They are severe disturbances driving the main vortices developing to the asymmetric state.At certain higher angles of attack,a U-shaped horseshoe vortex at the nose that checks the development of asymmetry containing the vortices cores of the main ones.At middle angles,both the horn vortex and horseshoe vortex are developed at the nose,the two types of the vortices have opposite effect on the asymmetry of the main vortices.