Experimental investigation of shock structure in turbulent Coanda jets

Abstract

Although Coanda surfaces are extremely useful for applications in industrial exhaust, the generation of noise in supersonic flows around such surfaces is not well understood. In order to effectively engineer a solution to this noise problem, the noise generation must be able to be accurately modeled. The two dominating generators of sound are turbulent mixing noise and shock associated noise (SAN). The first step necessary to model SAN is a precise predictor of the shock structure within the jet. A MATLAB algorithm is developed to translate Schlieren photos of the flow into qualitative shock location data. This data will be used in conjunction with the method of characteristics to create a model which predicts shock location around a Coanda surface for several slot widths and exit pressures.