Prediction of critical Mach number for store configurations

A numerical method is described and applied to the prediction of the critical Mach number of store configurations. A finite volume integral method is used to solve the full nonlinear potential equation in conservation of mass form. With the density held constant, the entire potential flowfield is solved by matrix iteration. The density field is then relaxed using the new potential values. The use of central differences for the velocity everywhere in the field is made possible by special treatment of the density terms in the coefficient matrix. The finite volume concept allows the boundary conditions to be treated in a simple and exact manner, without the use of a mapping scheme. Results are obtained for configurations that range from very thin pointed bodies to hemispherically blunt bodies. Excellent agreement is obtained for the pressure distribution over each body, even in supercritical flows, and the critical Mach number is easily and accurately computed. Finally, the computational advantages and capabilities of the numerical method are discussed and compared with other existing codes.