Helicopter Flight Dynamics Simulation with Continues-Time Unsteady Vortex Lattice-Free Wake and Multibody Dynamics

The objective of this study is the development of a helicopter flight dynamic analysis framework with state-of-the-art modelling and simulation techniques. The helicopter model consists of fully coupled continues-time unsteady vortex lattice method (UVLM)-free wake aerodynamic model with multibody dynamics, and is expressed in a set of first order Differential-Algebraic Equations (DAEs). The wake dynamics and multibody dynamics are solved simultaneously by one single general purpose DAE solver. An efficient trim methodology is proposed by constrained motion of the helicopter and Jacobian method, without introducing simplified model or numeric transient. The present method is validated against Caradonna-Tung test, Carpenter & Friedovich experiment and UH-60A maneuver flight test. The predicted airloads, wake geometry and aircraft motion response agree well with experiment data. The computational efficiency of present method is higher than that of time-marching free-wake while keeping good fidelity.