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Unsteady multigrid method for simulating 3-D incompressible Navier-Stokes flows on dynamic relative motion grids

An unsteady multiblock multigrid method is presented for simulating three-dimensional incompressible turbulent flows on dynamic grids, where the blocks may be in motion relative to one another. The artificial compressibility form of the three-dimensional incompressible Navier-Stokes equations is solved using a second-order time-accurate discretized Newton-relaxation scheme. The unsteady multiblock multigrid method is developed to accelerate the convergence of time-accurate solutions. The localized grid distortion technique is used to treat the relative motion of dynamic multiblock grids. Applications include an impeller, an isolated propeller, and a fully appended submarine with a rotating propulsor, which are presented to demonstrate the accuracy, efficiency, robustness, and applicability of the current method. (Author)