Optimization procedure for reduced sonic boom in high speed flight

A design optimization procedure for improved sonic boom and aerodynamic performance of high speed aircraft is presented. The rnultiobjectivc optimization procedure simultaneously minimizes the primary sonic boom, characterized by the first peak in the pressure signature, at a given distance from the aircraft and the drag-to-lift ratio (C_D/C_L) of the aircraft. The secondary sonic boom (characterized by the second peak in the pressure signature) is constrained below its reference value. Upper and lower bounds are also imposed on the lift coefficient. The flow equations are solved using a threedimensional parabolized Navier-Stokes solver. Sonic boom analysis is performed using an extrapolation procedure. The Kreisselmeicr-Steinhauser function is used for the multiobjective optimization formulation. A discrete semi-analytical aerodynamic sensitivity analysis procedure coupled with an analytical grid sensitivity analysis technique is used for evaluating design sensitivities. The use of the semi-analytical sensitivity analysis techniques results in significant computational savings. A nonlinear programming technique and an approximate analysis procedure arc used in the optimization. The optimization procedure developed is applied to a doubly swept wing-body configuration. Results obtained show significant improvements in the sonic boom characteristics and the aerodynamic performance.