Thus having a few (say 2-3) computational cells between the rotating impeller body and the diameter of the rotating RF cylinder is of utmost importance. The idea here is that you are solving the RRF separately from the global (rectangular) computational domain and the solver needs to transfer information back and forth. Thust would come from Force surface goal.īecause you are solving this problem using a rotating reference frame (RRF) approach, then in Step 2, you should make the cylindrical sketch (representing the RRF) slightly larger than the rotating propeller. Once again, Best thrust with less torque is the best choice. Take the best result from above and define a new parametric study.įix speed of advance (-Vz) and check a range of RPM around the required one. The goal is to overcome the hull drag, with the minimum required torque. Then, with fixed RPM, a range of fluid speeds around the required Ship speed, must be studied(-Vz in this model). Īs first step, an initial guess of the ship service speed, propeller RPM and hull drag must be known. In quite a rough way the thing would go as follows. It means that flow motion, thrust and torque are going to be computed for the "static" propeller condition which for most cases is not practical.įor a real analisys, a parametric study would be the way to go. Jehan: Define a fluid speed along the Z axis (Negative sign as it is a speed "relative" to the propeller)
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