Scattering from complex geometries using a parallel FVTD algorithm

A 3-D explicit finite volume algorithm has been developed to simulate scattering from complex geometries on parallel computers using structured body conformal curvilinear grids. Most simulations with realistic 3-D geometries require a large number of grid points for adequate spatial resolution making them suitable to parallel computation. The simulations have been carried out using a multi-block/zonal approach in the message passing paradigm on the SP-2. Each zone is placed on a separate processor and inter-processor communication is carried out using the Message Passing Library (MPL). Integration of the Maxwell's equations is performed using the four stage Runge-Kutta time integration method on a dual grid. This method of integrating on a staggered grid seems to give enhanced dissipative and dispersive characteristics. Results obtained in the past, have shown extremely good comparisons for scattering from the sphere and the ogive with the exact solution and standard FDTD type algorithms. Comparisons for non-axisymmetric targets like the NASA almond with experimental data has also been found to be extremely good. Scattering from complex 3-D bodies like a trapezoidal wing and an engine inlet has also been investigated.