3‐D multidomain PSTD for elasticity Free

A 3‐D numerical modeling scheme is developed in general curvilinear coordinates by using a multidomain pseudospectral time‐domain (PSTD) method. The computational domain is naturally divided into subdomains of piecewise homogeneous, curvilinear quadrilaterals conforming to the problem geometry. These curvilinear quadrilaterals are then mapped onto a unit square, where the spatial derivatives are approximated by the Chebyshev PSTD method. Characteristic conditions and physical boundary conditions are used to patch the solution between adjacent subdomains. A newly developed unsplit perfectly matched layer (PML) is used to absorb outgoing waves at the computational edge. This multidomain PSTD algorithm allows natural incorporation of curved boundaries into the numerical scheme, thus providing more increased flexibility and accuracy than the conventional finite‐difference method. The numerical scheme is validated by analytical solutions and by other numerical methods. Applications of this multidomain PSTD method will be shown for acoustic landmine detection.