An Exploratory Investigation of Cavitation Inception on the Pressure Side of Propellers

Delayed sheet cavitation inception has occasionally been observed in the MARIN Depressurized Towing Tank (DTT). The problems are specifically related to the pressure side of model ship propellers, and occur despite the application of leading-edge roughness. As a consequence, no cavitation at all or cavitation on parts of the propeller blades is observed, in cases where cavitation in the cavitation tunnel or at full scale is present. In an exploratory investigation, the effect of several parameters that may influence cavitation inception is studied in the DTT. In particular, the influences of Reynolds number, free-stream turbulence and additional gas nuclei are investigated. It is concluded that the presence of sufficient gas nuclei is crucial for sheet cavitation inception, even if leading-edge roughness is applied. With additional nuclei in the propeller inflow, sheet cavitation inception in the DTT is no longer delayed with respect to the cavitation tunnel.