Iterative Solution of 3D Helmholtz Equation with Approximate Boundary Conditions

The iterative solution of acoustic Helmholtz with BiCGStab solver is studied by using various boundary conditions: the second-order one-way radiation boundary condition (RBC2), the sponge layer, and the perfectly matched layer (PML). It turns out that the RBC2 has some limitations in accuracy and convergence. Although sponge layer and PML have similar numerical accuracies, PML is more efficient since it needs less additional layers for the absorbing media.