Numerical investigation into the unsteady aerodynamics of a ducted helicopter tail rotor under side-wind conditions

A numerical study into the unsteady aerodynamics of a ducted helicopter tail rotor is presented. Computations were carried out for ideal hover flight conditions and under the influence of side-wind. The results are validated against existing experimental performance data. The investigated numerical model incorporates the full annulus turbomachinery components as well as the entire tail boom including non-axis-symmetric casing contour, drive shaft fairing, fin and stabilisers. The rotor is characterised by an uneven azimuth-wise blade distribution, while the stator vanes complemented by the drive shaft fairing are distributed evenly. For the computational fluid dynamics analysis the fully turbulent three-dimensional Favre-averaged Navier-Stokes equations were solved on a Chimera grid system with 24.7 million cells. Besides thrust and shaft power characteristics, the varying blade loading due to the azimuth-wise position and the side-wind effect is analysed.