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

TL;DR

This paper introduces a novel fixed-wing adaptation method for simulating helicopter blade tip vortices, validated against wind tunnel data, offering improved accuracy over previous approaches.

Contribution

A new hybrid framework adaptation method for high-fidelity simulation of helicopter blade tip vortices, combining rotor code with fixed-wing models.

Findings

The method accurately reproduces flow around blade tips.

Validation shows good agreement with wind tunnel data.

Improved simulation of vortex roll-up compared to previous methods.

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 high-fidelity 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.