Unstructured Fixed Grid with Moving Body, Navier-Stokes Computational Fluid Dynamic (CFD) Solver for Simulating Gas Flows

The development of a generalized moving body capability for Computational Fluid Dynamics (CFD) flow simulations of highly transient flowfields is critical to system analyses of Divert and Attitude Control Systems (DACS) for Kinetic Warheads (KWs). Testing capabilities are limited in the DACS operating regime; therefore, computational tools are essential for such analyses. The flow in the DACS itself is characterized by high temperatures with extremely tight geometric clearances. These constraints make standard moving-grid techniques ineffective due to numerical stability constraints, cell collapse from body impact, cell impingement, and body pass-through difficulties. This proposal describes a novel technique that will allow for a generalized moving body capability within an unstructured fixed-grid (UFG) Navier-Stokes CFD flow solver. This approach will allow for an accurate solution on the fixed components as well as a full duty-cycle analysis of the valves. In addition, the time required for grid generation will be drastically reduced, thereby improving solution turnaround times. While the approach is directly applicable to Sea Based Midcourse ballistic missile defense, the solver developed could be widely applied to military and commercial applications where moving components or relative body motion is critical.