Hydrodynamic loads and wake dynamics of ducted propeller in oblique flow conditions

The hydrodynamic loads and wake dynamics of the ducted propeller in oblique flow are investigated by detached eddy simulation (DES), with particular emphasis on the characteristics of wake fields and kinetic energy (KE) spectra. The influence of the duct, together with the strengthened induction of the propeller, cause the non-uniform velocity distributions in the inflow plane, resulting in unstable and periodic hydrodynamic loads on the blades. Shedding vortices from the leading edge of the duct dominate the leeward wake, and strengthen the self- and mutual induction of tip vortices. Large deformation of the tip vortices is observed due to the complex interference of the shear-layer vortices, shedding vortices and secondary vortices. The trajectories of the tip vortices are found distorted but still recognisable on the windward wake. The spiral-to-spiral distances of tip vortices increase and the re-alignment effect of the main flow enhances in the downstream wake.