Wind tunnel tests on the influence of propeller loading on ship rudder performance: four quadrant operation, low and zero speed operation

The results of wind tunnel tests on a rudder operating downstream of a propeller are presented. The experiments simulated the condition of a rudder operating in the proximity of a propeller but without the influence of the hull. The tests were carried out in the 3.5m x 2.5m wind tunnel at the University of Southampton and form an extension to the basic rudder-propeller tests which have already been carried out and are reported on elsewhere. The rudders tested were all movable, and the propeller used in the tests was modelled on a Wageningen B4.40. Tests were carried out with positive and negative wind speed and positive and negative propeller revolutions in order to simulate all the four quadrants of operation. These tests also included the case of zero and low wind speed. Results are presented as rudder lift, drag and moment coefficients and centre of pressure for selected angles of attack and changes in propeller thrust loading. Surface pressure distributions over the rudder were also obtained in selected cases in order to provide a detailed knowledge of the distribution of forces over the rudder. The results provide rudder force data for use in manoeuvring simulations and detailed data for the validation of numerical modelling of the interaction problem.