Transition to Transonic Flow in the Far Field for a Supersonic Airfoil in a Stratified Atmosphere.

摘要

This paper deals with the steady frictionless, nonheat-conducting flow field of a thin airfoil in an atmosphere with a weak wind gradient. Because of this wind gradient, which is assumed to increase linearly with altitude, the flow gradually becomes transonic in the far field below the airfoil. This transition phenomenon also occurs in an atmosphere where the temperature decreases with altitude, and for certain cases of accelerating flights. In all these models, it is shown that a solution which describes both supersonic and transonic regimes can be derived by matching two expansions. The flow field in the transonic region is then calculated numerically using the method of characteristics and incorporating the appropriate shock relations.