High-Fidelity Cfd Maneuver Simulation Using Blade Dynamics, Flight Mechanics And A Pilot Model

Abstract

High-fidelity CFD simulations for stationary flight have become state of the art for many years now, including fluidstructure coupling to blade dynamics and flight mechanics to reach a trimmed state. Unsteady maneuver simulations utilizing CFD are much more scarce, mainly due to the huge computational effort required to run for serveral tens or hundreds of revolutions, and thus more often rely on mid-fidelity aerodynamics. Continuous advances in High Performance Computing now allow the application of CFD to relevant macroscopic maneuvers, allowing an investigation of scenarios for example like vortex ring state, which are highly affected by interactional dynamics, and where midfidelity tools are less robust and reliable. The paper describes the challenges and possible solutions when progressing a well-established high-fidelity CFD framework from stationary flight to unsteady maneuvers, analyzing the physical causes of problems encountered, and further objectives to be addressed. Examples given for a Robinson R44 helicopter model include a slalom flight, a quickstop maneuver, and vortex ring state, including several evasive methods.