A STUDY OF THE FORCES ACTING ON RUDDER WITH RUDDER ANGLE BEHIND PROPELLER

In a previous report, the authors gave the results of the calculation of flow around a rudder with the rudder angle behind a propeller in uniform flow, applying the simplified propeller theory of the infinite number of propeller blades to the propeller and the panel method to the rudder. The calculated results were compared with existing measured velocity and pressure distribution. Good agreement of the calculated and measured results was obtained within the rudder angle range of 20o. This report discusses forces acting on a rudder with rudder angle, and the interaction between propeller and rudder, using the same method with some improvements. The calculated results of forces acting on a rudder with rudder angle and of the effects of rudder angle on propeller performance show good agreement with experiments within the rudder angle by 20o. For a rudder angle of more than 30o, the calculated drag and moment acting on the rudder is different from that of the measurements. It is considered that this is due to different pressure distribution on the rudder in between the calculation and experiment. Some improvements of the calculation method in the large rudder angle behind the propeller are necessary, applying a method such as the massive separation flow model.