Parallel Computation of Three-Dimensional, Unsteady Wake Flows Using VortexMethods

摘要

The objectives of the research were to develop computational techniques forparallel computers capable of simulating complex, three-dimensional, unsteady wake flows at high Reynolds numbers and to apply these techniques to such flows as those about maneuvering three-dimensional bodies. A Lagrangian vortex method was used as a basis for the numerical scheme. In vortex methods, the only grid required is that to mesh the surface of the body. In addition, the computational elements containing vorticity move with the local fluid velocity and are required only in the boundary layers and wake of a bluff body flow. This technique is therefore a natural candidate for the simulation of wake flows in that the fluid containing vorticity for these flows occupies only a small fraction of the total fluid volume of interest. A robust vortex particle method for three-dimensional flows was developed, including a new treatment of viscous effects to allow for the accurate treatment of boundary layer mechanics including unsteady separation. In addition, to allow for ambitious, three-dimensional applications, fast algorithms were developed for both the vortex particle method and the panel method (used to satisfy the no-slip boundary condition on the body surface).