Field Velocity Approach and Geometric Conservation Law for Unsteady Flow Simulations

Abstract

A technique to model unsteady flow phenomenon which involve simultaneous elastic motions of the boundaries and interaction with gust fields is discussed. The field velocity approach is used to include the effect of the gust fields caused by a vortex wake in to the flow computations. Elastic deformations of the boundaries causes changes in grid cell volumes which requires the rigorous enforcement of the Geometric Conservation Law. Mathematical modeling required to enforce conservation when performing such unsteady flow computations is detailed. The application of the technique developed to a variety of problems from simple 2-D model problems to more complex realistic problems are detailed. The predictions obtained are validated with exact analytical results/ experimental data as appropriate. Overall, the field velocity approach together with a technique to enforce the Geometric Conservation Law is found to provide a powerful tool for unsteady flow simulation.