Truncated transparent boundary conditions on open boundaries for isotropic media

Formulas for Truncated Transparent Boundary Conditions (TTBC) for isotropic media are presented for all boundaries of 3D computational domain. A method for modification of the TTBC at edges and vertexes of computational domains and the corresponding finite-difference scheme are suggested. The TTBC are compared to known characteristic boundary condition. Dependency of amplitude of the reflected wave on size of the computational domain is investigated.