CFD OPTIMIZATION OF A THEORETICAL MINIMUM-DRAG BODY

This article describes a methodology behind coupling a fast, parabolized Navier-Stokes flow solver to a nonlinear constrained optimizer. The design parameters, constraints, grid refinement, behavior of the optimizer, and flow physics related to the CFD calculations are discussed. Pressure drag reduction in the supersonic regime of a theoretical minimum-drag body of revolution is performed. Careful selection of design variables allows the optimization process to improve the aerodynamic performance. A calculation including nonlinear and viscous effects produces a different minimum drag geometry than linear theory and results in a drag reduction of approximately 4%. Effect of grid density on the optimization process is also studied. In order to obtain accurate optimization results, CFD calculations must model physical phenomena that contribute to the optimization parameters.