PREDICTING EXHAUST PLUME BOUNDARIES WITH SUPERSONIC EXTERNAL FLOWS

Several methods for predicting exhaust plume boundaries with a surrounding external flow currently exist, Unfortunately, these methods are usually cumbersome and often expensive, since they may be computationally intensive. Also, these methods typically provide many flowfield details in addition to the plume boundary location, If only the latter is desired, then calculation of these other details is wasted effort. This concern resulted in the development of a simplified plume boundary prediction method capable of analyzing underexpanded nozzle now exhausting into a supersonic external now. This new method is based upon the well-established Latvala method and uses an iterative scheme that employs two-dimensional flowfield assumptions, However, the method is still applicable to axisymmetric plumes, and its simplicity permits efficient operation on personal computers, Predictions of boundaries for axisymmetric plumes surrounded by various high-speed external flows exhibit excellent agreement with empirical data, and parametric studies indicate that trends are correctly predicted.