Model for jet noise analysis using pressure gradient correlations on an imaginary cone

In previous applications of the method for estimating the noise‐generating regions of a jet from correlations of the acoustic pressure gradient near the boundary of the jet, plane surfaces were used for measurement purposes. However, since the boundary of an axisymmetric jet is approximately conical in shape, more relevant data can be obtained through measurements on an imaginary conical surface surrounding the jet. Hence, in preparation for experimentation on a round supersonic jet, the mathematical model necessary to utilize a cone in this method has been developed. The model is proven correct by comparison of the acoustic intensity flux through the cone as determined from this formulation and from exact means when a known source is used as the noise generator. An apparent source distribution on the surface due to the actual source is calculated to determine the feasibility of identifying the actual source in terms of correlations on the surface. The contribution to the farfield intensity is found to be...