A comparison of two methods for calculating solid angle coefficients in a BIEM numerical wave tank

By taking the simulation of nonlinear numerical wave tank using the boundary integral equation method (BIEM) as an example, direct and indirect methods are used to compute solid angle coefficients (also named as free-term coefficients). The computing precision and cost are compared between these two methods. The comparisons show that the same good numerical results can be obtained for both direct and indirect methods, and the computing cost of the indirect method is greater than that of the direct method, especially for larger calculation domain.