High speed weapons systems, particularly hypersonic vehicles (HSV), operate in a high energy environment characterized by strong fluid, thermal, and structural interactions that must be adequately modeled in order to design the vehicle and its flight control laws. Due to a lack of ground test facilities which can generate the high energy environment of interest, the primary course of investigation must be through computational simulations. However, because of the highly coupled and generally complex processes that play integral roles in the performance of a HSV, the reduction of HSV states to manageable numbers has been a daunting task and posed as a significant hurdle to the timely evaluation of vehicle response and stability. Current computational research efforts have focused on either improving particular physics model fidelity with limited discipline interactions due to a high computational cost, or including many discipline interactions using very simple models. Thus, there is a wide middle-ground between the low-fidelity, high-interaction and high-fidelity, low-interaction modeling regimes that has yet to be considered, but is critical to the development of high speed weapons systems. This has resulted in an important need within the numerical analysis software market (> $2M) for a numerical simulation framework that allows multi-disciplinary, multi-fidelity modeling and analysis of flexible hypersonic vehicles.
Simulation Framework for Multidisciplinary Reduced-Order Modeling and Aerothermoelastic Analysis of Hypersonic Vehicles
Research on numerical simulation frameworks for HSV at the Department of Aerospace Engineering in University of Michigan has led to a full 6 degree-of-freedom simulation code with various physics that alter the aero-thermo-elastic-propulsive equilibrium of the vehicle. A partitioned-based solution is employed to approach the problem of modeling a flexible hypersonic vehicle by dividing the vehicle into discrete regions within which unique combinations of physical processes are relevant. The dominant physics of each region are then modeled locally and information is exchanged across region interfaces at predetermined time intervals as the vehicle simulation is marched forward in time. The highly coupled physical processes within each region are modeled using an array of variable fidelity reduced order models. The proposed simulation framework introduces the capability to analyze the dominant physics needed for the generation of control-oriented models and will provide a reference model for flight control evaluation.
- control evaluation for high speed vehicles
- HSV trim, time simulation, and aeroelastic stability analysis
- trajectory analysis and the aerothermoelastic effects on HSV
- Full 6 degree-of-freedom simulation capability
- Multi-disciplinary, multi-fidelity approach to aerothermoelastic/propulsive interactions