Computing turbulent flow in complex geometries on a massively parallel processor

Abstract

In this paper, we present parallel implementations of two methods for computing turbulent flow in complex geometries. Both methods are based on the random vortex method, which is particularly suited for com­ puting complex, viscous, incompressible flow across a wide range of flow regimes and characteristics. The first method is a full vortex method, designed to accu­ rately simulate such fluid phenomenon as vortex shed­ ding, merger, and rollup, as well quantitative features of the flow. The second method, based on a vortex­ in-cell method, is an extremely fast version which can offer qualitative portrayal of the dominant fluid structures and mechanisms useful in the design stage. Both methods are non-standard, containing few of the positive attributes commonly associated with methods that easily lend themselves to massively parallel implementations. They are Lagrangian schemes, in which the position of each computational element is affected by all others at each time step. The efficient execution of these methods on a Connection Machine CM-2 requires parallel N-body solvers, parallel elliptic solvers, and parallel data structures for the adaptive creation of computational elements on the boundary of the confining region.