Multi-criteria design optimization of two-dimensional supersonic inlet

Multi-criteria Design Optimizations (MDOs) are performed for a 2-D mixed compression supersonic inlet intended for an air breathing missile. The multiple criteria are the optimization of specific objective functions based on the inlet performance for three different stages of the missile mission, i.e., the mass capture ratio ε during acceleration, and the total pressure recovery coefficient n during cruise and maneuver. The MDO yields the Pareto Front in the space of the objective functions. Three different MDOs are performed based on two different flow solvers. The first MDO employs the semi-empirical inlet analysis code OCEAS, developed by Aerospatiale Matra Missiles. OCEAS requires typically 2 sec cputime per simulation, but is limited to inlets with entirely supersonic flow upstream of the inlet throat. The second MDO employs 2ES2D, developed by Aerospatiale Matra Missiles and Rutgers University. 2ES2D requires typically 2 minutes cputime per simulation, and can treat inlets with mixed subsonic/supersonic flow upstream of the inlet throat. The third MDO employs both OCEAS and 2ES2D in a self-adaptive methodology whereby OCEAS is employed except for those configurations where subsonic flow occurs upstream of the inlet throat. The self-adaptive methodology yields essentially the same Pareto Front as obtained using 2ES2D alone but with a 40% reduction in cputime. The Pareto Front obtained using the self-adaptive methodology or 2ES2D exhibits significantly better designs than the Pareto Front obtained using OCEAS alone.