Acoustics design sensitivity analysis for the noise optimization of landing gears

Abstract

This paper provides a new Acoustic Design Sensitivity (ADS) method for the minimization of noise on landing gear parts. The idea consists of direct differentiation of the closed-forms expressions of the acoustic pressure levels with respect to the landing gear design parameters. The outlines of the method are presented herein by considering semi-empirical formulations proposed for the acoustic pressure level but can be straightforwardly applied to other acoustics weak integral formulations or analogies. Indeed, the estimates of the noise level derivatives allow assessment of the most acoustically sensitive design parameters. Numerical implementation of the ADS method has been performed using SCILAB open code and validated by comparing with the derivatives calculated using Finite Difference Methods (FDM). Then, the sensitivity estimates have been used to minimize different (SPL and OASPL) noise objectives for a generic landing gear. The numerical examples clearly demonstrated the ability of the (ADS) method to accurately identify the appropriate design parameters that will control the bulk of the noise sensitivity. In addition, the optimum solution of the noise minimization problems is exclusively dependent on these design parameters.