Numerical investigation of the vortex roll-up from a helicopter blade tip using a novel fixed-wing adaptation method

Abstract

This contribution relates to the simulation of the flow around the tip of a helicopter rotor blade in hovering flight conditions. We here propose a new methodology of framework adaptation, using a comprehensive rotor code and highfidelity numerical simulations. We construct an equivalent fixed-wing configuration from a rotating blade, in which centrifugal and Coriolis forces are neglected. The effect of this approximation on the solution is analysed. The method is validated by a detailed comparison with wind tunnel data from the literature, concerning aerodynamic properties and tip vortex roll-up. This validation also includes variations of the pitch angle and rotational speed, up to transonic tip velocities. Compared to previously published methods of framework adaptation, the new hybrid method is found to reproduce more accurately the flow around a rotating blade tip.

Blade-Tip Vortex Noise Mitigation Traded-Off against Aerodynamic Design for Propellers of Future Electric Aircraft

“…It is worth noting that there are no streamwise long vortex tubes formed along the joined round blade tip. This effect is apparently different from a classical blade tip [27] or airfoil side edge [28], where vortex tubes are induced from the blade pressure and suction sides and merge in the downstream wake. Such streamwise vortex tubes are also observed for Conprop-3 and -6.…”

Robust optimization of the aerodynamic design of a helicopter rotor blade based on multi-fidelity meta-models

“…This normalization allows to account for the influence of the sheared inflow. 65 Figure A.3-c shows the computed pressure coefficients at a normalized spanwise location of 0.89. The results are plotted versus normalized chordwise distance depicting a good agreement with measurements with a maximum uncertainty of 8% in the inner part of the chord blade.…”