A hybrid Navier-Stokes / viscous vortex particle wake methodology for modeling maneuver loads

Abstract

Maneuvering flight and high-speed flight are critical design points in any rotorcraft's operating envelope. These conditions give complex flow phenomena, creating high stresses and vibrations. To accurately predict the flow properties over the relatively flexible rotor blades, coupling between computational fluid dynamics (CFD) and computational structural dynamics (CSD) is required. In this work, GT-Hybrid, a hybrid wake rotorcraft CFD code that is coupled to DYMORE, is used. A vortex particle method has been implemented, in place of the existing lattice wake methodology. Selected UH-60A maneuvering flight conditions; being two diving-turn and pull-up maneuvers, are simulated using the vortex particle method. Results are compared qualitative with those using the traditional wake method and available experimental data; indicating that using the vortex particle method gives similar or better results. Additionally, computational efficiency is improved by using the vortex particle method and time savings exist in every simulation.