Far-Field Analysis of Hovering Helicopter Rotor

This paper presents the evaluation of the far-field drag analysis and its application to helicopter rotor in hover. This method widely used for fixed-wing configurations has only recently been extended to rotary wing in S. Verley's PhD thesis. Based on these developments, the far-field torque analysis is applied to a realistic rotor case including the blade root area using three different grid topologies: a coarse monoblock grid, a medium multiblock grid and a fine chimera grid. Near-field predictions are obtained through standard integration while Far-field results are obtained using the proposed present approach. Comparisons of near-field and far-field results are presented and discussed. The far-field breakdown is in particular detailed and it is demonstrated how the far-field analysis can be used to locate rotor torque sources.