Characterizing scattering coefficients numerically via the fast multipole accelerated boundary element method.

Various panels are used in acoustical installations to provide desired characteristics to spaces to be used for listening. These panels have complex shapes with geometrical features that have sizes corresponding to wavelengths of sounds of interest. The complex interaction of acoustical waves with these shapes is what gives these surfaces their desirable properties. Experimental characterization of the acoustical properties of these surfaces under random and specular incidence is relatively time consuming. An alternate procedure is to numerically simulate the scattering behavior, and then computing the coefficients of interest from the simulation. A significant obstacle to such computations is the time taken for simulation. Fast multipole acceleration of boundary element methods [Gumerov & Duraiswami, J. Acoust. Soc. Am. 125 (2009)] is a promising approach to speeding up computations. We report on the application of this method to the computation of various scattering coefficients.