Simulation of Flexible Hypersonic Vehicle Flight Dynamics for Flight Control Evaluation

Student : Ryan Klock

Sponsor : AFRL


Hypersonic vehicles operate in an extreme flight environment that induces strong fluid, thermal, and structural interactions. To design and evaluate these vehicles, we must have a robust understanding of all driving physical processes and their couplings. Classically, investigation of a vehicle design would be through testing of a physical model in a wind-tunnel or other ground facility. However there are currently few to no facilities capable of generating and maintaining a hypersonic flow at a scale sufficient to perform realistic testing. Thus our main course of investigation must be through numerical simulation. But here too, we find there is a problem. State of the art simulation tools are either high-fidelity single discipline models that are slow and costly to run on large computer clusters, or are a collection of low-fidelity or fundamental models that are closely coupled, yet do not provide trustworthy results due to their simplifying assumptions. Reduced-order models offer a middle-ground by predicting the results of high-fidelity analysis tools at a rate sufficiently fast to allow moderate coupling. Using reduced-order modeling techniques, our lab has developed a simulation framework based on a component partitioning approach that allows vehicle trimming, stability analysis, and time-domain simulation of a growing portfolio of hypersonic vehicle designs and mission types.

An example of how a vehicle may be partitioned and simulated using model combinations relevant to each component.
Our growing portfolio of hypersonic vehicles.

An example aeroelastic simulation of the AFRL IC3X High Speed Vehicle with closed-loop control.

Elastic deformation encountered during a maneuver. (1/16th playback speed, deformation exaggerated 100x)