n efficient boundary element method (BEM) solver is developed in AANTC is compute the sound scattering from the objects, which can be acoustical hard or impedance walls. Reduced order modelling technologies are employed to improve the computational efficiency, and special treatments are conducted to remove the unphysical instabilities modes. The solver has been applied to drone fuselage scattering and acoustic window performance estimation. Ref. Hanbo Jiang, et al., Boundary element analysis on fuselage scattering of drone noise, International Journal of Aeroacoustics, pp. 1-14, 2022.