Computation of Hypersonic Flow about Maneuvering Vehicles with Changing Shapes

Ferencz, R M ; Felker, F F ; Castillo, V M

Lawrence Livermore National Laboratory

关键词: Missiles;    99 General And Miscellaneous//Mathematics, Computing, And Information Science;    Reentry;    National Security;    Steady Flow;   

DOI  :  10.2172/15009796
RP-ID  :  UCRL-TR-202587
RP-ID  :  W-7405-ENG-48
RP-ID  :  15009796

美国|英语

来源: UNT Digital Library

【 摘 要 】

Vehicles moving at hypersonic speeds have great importance to the National Security. Ballistic missile re-entry vehicles (RV's) travel at hypersonic speeds, as do missile defense intercept vehicles. Despite the importance of the problem, no computational analysis method is available to predict the aerodynamic environment of maneuvering hypersonic vehicles, and no analysis is available to predict the transient effects of their shape changes. The present state-of-the-art for hypersonic flow calculations typically still considers steady flow about fixed shapes. Additionally, with present computational methods, it is not possible to compute the entire transient structural and thermal loads for a re-entry vehicle. The objective of this research is to provide the required theoretical development and a computational analysis tool for calculating the hypersonic flow about maneuvering, deforming RV's. This key enabling technology will allow the development of a complete multi-mechanics simulation of the entire RV flight sequence, including important transient effects such as complex flight dynamics. This will allow the computation of the as-delivered state of the payload in both normal and unusual operational environments. This new analysis capability could also provide the ability to predict the nonlinear, transient behavior of endo-atmospheric missile interceptor vehicles to the input of advanced control systems. Due to the computational intensity of fluid dynamics for hypersonics, the usual approach for calculating the flow about a vehicle that is changing shape is to complete a series of steady calculations, each with a fixed shape. However, this quasi-steady approach is not adequate to resolve the frequencies characteristic of a vehicle's structural dynamics. Our approach is to include the effects of the unsteady body shape changes in the finite-volume method by allowing for arbitrary translation and deformation of the control volumes. Furthermore, because the Eulerian computational mesh for the fluid domain must be attached to the vehicle as it undergoes potentially high accelerations, that mesh must be viewed in a non-inertial coordinate frame. The usual conservation-law form of the fluid dynamic governing equations must be augmented. This approach thus requires the derivation of a significantly new numerical formulation, especially to incorporate a modern flux-splitting methodology as needed for numerical stability and accuracy.