Measuring Ship Propeller Side Forces
 

Hi everyone

I am trying to measure a ship propeller characteristic performance coefficients namely KT, 10KQ and h0 and their components in x, y ,z directions. But I'm having difficulties with KTy,z and 10KQ,yz

When calculating performance curves in x direction everything is fine and my errors are less than 3% comparing to experimental results of the literature. But at the same time when I want to extract y and z components of thrust and moment, the results are odd since the numbers are very small! Usually y and z components are one order smaller than x components but I get values of O(-4)!
I can't work it out and tried every motion technique from MRF to Sliding mesh to polyhedral mesh and I still get the same values.

I know that y and z components are viscous driven so I checked my Y+ and its as low as 0.1< Y+ < 11 all over the prop. which seems fine. (My turbulence model is k-w SST)

Any suggestions?
Thanks in advance

Hello Soroush,

Have you solved this issue? I would recommend first checking the report itself. It is easy to have a report with an incorrectly assigned part, coordinate system, direction, representation, etc.

If this doesn't work I would recommend looking at contours of the wall shear stress to see if they are also unexpectedly low. Then there might be an issue with the wall boundary condition on the propeller.

Thank you for the reply

The reports seem ok since I double checked it again and It was fine.

The saying about wall shear stress and wall boundary condition is an interesting theory. I'll look into it to see if I can find something out