An Optimization Process to Maximize Aircraft Nacelle Active Noise Attenuation

NASA?s current aircraft noise reduction research focuses on reducing the perceived noise levels of future aircraft by a factor of two. This Phase I effort will generate fast accurate finite difference algorithms for use in active noise design of inlet nacelles. This includes an analytical correlation of the geometrical parameters necessary to quickly maximize the attenuation of an active noise system. The secondary noise actuator size and number, position in relation to the primary noise source, angular orientation as well as other geometrical and acoustical properties will be evaluated in the optimization process to determine the maximum possible attenuation. Using this correlation as a starting point, the full numerical solution can be used to fine-tune the parameters for the particular complex engine geometry under consideration. The new algorithm will lead to more efficient use of active control and provide NASA and industry a revolutionary tool for planning and accessing future noise attenuation goals.