Hey all,

I am trying to run a flow simulation on some new rudder designs. I basically want to figure out some lift and drag forces. To do this I was looking at forces in the x and y direction. Attached is the solidworks file. When I run the simulation at a 7 degree angle of attack (4m/s in x direction, 0.49m/s in the y direction) the x component of force (the drag part) is indicating that it is negative, implying that the rudder has negative drag. I double checked and am not mixing up any signs, and it appears to have significant lift (800N) or so. I am a student doing an independent study and trying to learn the software as well, so any help would be greatly appreciated.

A secondary question: I have been struggling out how to make my model a bit more complex. The current simulation just restricts my fluid range to where the water line is (343mm down from the top of the rudder). It would be much better if I could have two fluids, air above that line and water below, as i can experiment with different mounting solutions for the rudder head which connect just above the water line.

Best,

Josh