Application of the pFFT algorithm to the hybrid-domain boundary element method for acoustic problems

The pre-corrected fast Fourier transform (pFFT) algorithm is applied to accelerate the hybrid-domain boundary element method (BEM) for acoustic problems. Based on the previous successful applications of this algorithm to the BEMs for the exterior domain and interior domain acoustic problems, the implementation of this algorithm in the hybrid-domain BEM for acoustic problems is studied in detail. To validate the present method, the simulation on a spherical Helmholtz resonator is carried out. The numerical results are compared with those obtained by the direct multi-domain BEM and the resonance frequency is compared with the corresponding approximate solution. As expected, the present results agree well with those found by the direct BEM. But the remaining problem is that the GMRES solver without a pre-conditioner converges very slowly for the hybrid-domain BEM.