Application of computational fluid dynamics to sonic boom near- and mid-field prediction

A technique combining a quasilinear extrapolation theory and a three-dimensional parabolized Navier-Stokes (PNS) code has been used to calculate the supersonic overpressure from three different geometries at near- and mid-fields. Wind-tunnel data is used for code validation. Comparison of the computed results with different grid refinements, and different extrapolation distances, are shown in this article. It is observed that a large number of grid points is needed to resolve the tail shock/expansion fan interaction. Therefore, an adaptive grid approach is employed to calculate the flowfield. The effects of a thin, attached boundary layer and the sting of the wind-tunnel model to the sonic boom have also been studied in this article. The agreement between the results and the wind-tunnel data confirms that this technique can be applied to the problem of sonic-boom prediction.