Simulation Environment for CFD-based Aeroelastic Analysis of Aircraft

Abstract

The development, validation and application of a RANS-CFD-based simulation environment for aeroelastic analysis of aircraft in the time domain are presented. The core element of the simulation environment, developed in the sense of a partitioned approach, is the Aeroelastic Coupling Module (ACM). It couples specialized high-fidelity methods for the individual problems of aerodynamics, structural dynamics, and CFD mesh deformation to a versatile overall aeroelastic solver. Central validation test case is the HIRENASD experiment---a static and dynamic aeroelastic wind tunnel test campaign in transonic flow at real flight Reynolds numbers. The agreement of the numerical predictions with measurements of the static tests is evaluated in detail for independent variations of angle of attack, Mach number, load factor and Reynolds number, as well as for different turbulence models; shock-boundary layer interactions and flow separation behavior are analyzed. In the dynamic tests with excitation of the model in selected natural vibration modes, the separate influences of CFD mesh refinement, turbulence model, Mach number and Reynolds number on the agreement with the experiment are investigated. In addition to simulations with prescribed experimental model vibration, results from fully coupled simulations of the dynamic HIRENASD experiments are presented---simulations in which the model excitation from the aeroelastic equilibrium to the stationary harmonic oscillation is simulated exactly according to the model excitation procedure in the wind tunnel tests. In all cases, the essential effects observed in the experiments are predicted very precisely by the simulation, even the increased aerodynamic damping at high flight Reynolds numbers.