Multi Objective Aeroacoustic Design Exploration of Launch Pad Flame Deflector Using Large Eddy Simulation
This study explores possible design of an aeroacoustic flame deflector for a rocket launch pad. The design objectives are 1) minimization of the overall sound pressure level near the payload fairing, 2) minimization of the time averaged maximum pressure on the flame deflector surface, and 3) minimization of the shape difference from a flat plate inclined at 45 deg. The acoustic wave characteristics associated with deflector shapes are identified by large eddy simulations. To overcome difficulties of required computational time, the following are adopted: 1) a high order scheme that reduces the computational cost of large eddy simulations, 2) a multi objective evolutionary algorithm for efficient parallelization, and 3) large scale parallelization on the Japanese supercomputer "K" Total computational time for optimization is approximately 350 h with 6500 processors of the K computer. The analysis of nondominated (Pareto optimal) solutions reveals a tradeoff relation and correlation among the objective fun.