Analyzing Low-Speed Rotor-Fuselage Interactions: A Comparative Study Of Simulations And Flight-Test Data On H175

Abstract

In this work, comparisons between simulations & measurements in flight are proposed for different low-speed flight conditions out of ground effect on an Airbus Helicopters H175 PT1 rotorcraft equipped with a 5-bladed Spheriflex® rotor. Numerical results have been obtained by full-helicopter unsteady simulations relying on a single-rotor loose coupling approach between the Computational Structure Dynamics & Computational Fluid Dynamics parts, assuming blade elasticity and six degrees-of-freedom trim. One flight condition is tackled with both rigid-blade and elastic-blade modelling so as to highlight the influence of the blade softness on the results. The paper showcases good agreement between the simulation results & flight-test measurements regarding variations of main-rotor collective pitch, airframe attitude angles, rotor power & rotor loads with true airspeed. Airframe download is also numerically analysed.