Assessment of CFD methods against experimental flow measurements for helicopter flows

A novel experimental and computational aerodynamic database for a complete helicopter has been generated for the GOAHEAD project. The primary objective of the five-year long project was to validate state-of-the-art CFD solvers developed for rotorcraft aerodynamic problems against experimental measurements. The present work is focused on the CFD aspects of the project and the numerical simulations conducted by the GOAHEAD partners after the experimental activities. To enhance our understanding of complex dynamics governing a helicopter flow, seven test cases, corresponding to different flight conditions parameters, were simulated: three isolated fuselage cases, a low speed pitch-up case, a cruise and high-speed tail-shake case and a highly loaded dynamic stall. The flight condition parameters for the CFD computations were calibrated according to the wind-tunnel experimental conditions. The predictive capabilities of the employed CFD solvers were assessed through comparisons with experimental data. CFD predictions provided an overall good agreement and rich flow-field details although there is a number of discrepancies that are highlighted and analysed in this study.