Semi-empirical Flow Separation Model For Overexpanded Rocket Nozzles

A new semi-empirical flow separation model for over expanded nozzles has been developed. This model ought to serve for prediction of flow separation in TIC nozzles at arbitrary nozzle pressure ratio. Several cold gas tests were conducted at DLR test facilities to approve the central elements of the separation model. To determine the physical separation point pressure sensitive paint and the lately developed back flow frosting were used as visual measurement methods. The incipient point of the shock boundary layer interaction was visualized by infrared thermography. Additionally the course of the oblique shock and the shear layer boundary could be approved by schlieren photographs taken during test runs.