Time-Dependent Calculation of Acoustic Radiation From Finite Wings Using BEM

Abstract

The calculation of acoustic radiation from finite wings using a 3D, time-domain Boundary Element Method (BEM) was investigated. Numerical convergence was studied and solutions obtained using an extrapolated convergence method were used to compare to 2D analytical solutions. Frequency-domain lift solutions were found to be accurate to less than 5% using relatively coarse grids (Δx ∼ 0.1) for reduced frequencies above 0.1 and less than approximately 3. The acoustic responses for high aspect ratio wings were found to agree well qualitatively with the 2D results. As an illustration of the capabilities of the method, a full-span, flapped wing configuration undergoing oscillatory motion was considered with a preliminary quantification of the aeroacoustic influence of the flap.