The manuscript “Influence of the number of blades on the wake development of rim-driven thrusters”, co-authored by Drs. Antonio Posa and Riccardo Broglia from CNR-INM and Prof. Stefano Gaggero from the University of Genoa, was selected as featured paper by Physics of Fluids and for Scilight by the American Institute of Physics.
High-fidelity simulations are exploited to analyze the wake features of rim-driven thrusters. They are unconventional marine propellers, whose blades are installed on a rim rotating within a slot in their nozzle, rather than on a rotating hub. This particular geometry avoids the onset of both outer tip vortices and a large axial vortex, typical of conventional propellers, which are sources of cavitation phenomena, noise and unsteady interactions with downstream maneuvering devices. In contrast, they are replaced by inner tip vortices, which the study by Posa, Gaggero & Broglia found substantially less intense than those populating the wake of conventional marine propellers. These features result in an order of magnitude mitigation of the peaks of negative pressure and turbulent stresses, with beneficial outcomes on the wake signature of this class of unconventional propellers. The same study also explores the influence of the number of blades on the wake properties of rim-driven thrusters.
More details can be found in Physics of Fluids at https://doi.org/10.1063/5.0314358 and in Scilight at https://doi.org/10.1063/10.0043021.