THE AERODYNAMICS AND AEROACOUSTICS OF ROTATING TRANSONIC FLOW FIELDS

A study of the aerodynamic flow field about a 2-D transonically rotating disturbance has been conducted using computational results obtained from the Potential Transonic Small Disturbance Equation transformed to a rotating reference frame. The disturbance considered is a half circular arc bump, which rotates at a high subsonic Mach number. The phenomenon known as “delocalization” -- the propagation of shock waves into the far field from a subsonic rotating disturbance -- is simulated through a sequence of increasing rotational Mach numbers. Computational results are graphically displayed showing delocalization occurring. The effect of radius/chord ratio and thickness ratio on the onset of delocalization is also examined. Results indicate that the higher the radius/chord ratio, the greater the rotational Mach number before the occurrence of delocalization. As expected, the results of the thickness ratio show the converse. An experimental model for verifying the results is briefly described. This model provides the same mechanism for the propagation of shock waves from a subsonic disturbance as is present for a 3-D rotor blade and is considerably simpler.