Calculation of annular nozzle trisonic flowfields by the method of characteristics

Abstract

A numerical algorithm based on the unsteady two-dimensional method of characteristics is presented for calculating axisymmetric inviscid trisonic (i.e., subsonic-transonic-supersonic) flowfields in annular nozzles. The algorithm is an explicit second-order accurate predictor-corrector procedure. An inverse marching method based on a local network of wavelines and the pathline is employed wherein the solution grid in physical space is prespecified. An orthogonal uniform transformed space, obtained by an algebraic grid generation method, is used for flow property interpolation in the initial-data surface. Steady flow solutions are obtained as the asymptotic solution in time. Results for four annular nozzles are presented. Comparison of the predicted and measured wall pressure distributions and nozzle efficiencies shows good agreement.