Experimental investigation of a propeller jet induced velocity field.

The velocity field of a propeller jet induced by two different propellers has been investigated using the PIV technique in a still water basin with fixed bed. The main novelty is represented by the presence of a stern of an inland vessel model. The angles and distances of jet impact and maximum bed velocity have been evaluated from the measured instantaneous velocity fields. Time averaged velocities of the horizontal component, V , have been determined at different distances from the propeller plane. The velocities especially close to the bottom are higher for the Kaplan propeller than for the Wageningen propeller. The results have been compared with existing empirical formulas. Differences between calculated and measured values systematically depended on the considered combination of propeller, rudder, and ship. These results reflect the empirical character of the equations and highlight not considered parameters.