[ali_ebrahimi]

Hi
I work in the field simulation CFD high speed planing in STAR CCM+.
I want to calculate Hydrodynamic & Aerodynamic Liftseparately in multiphase flow (water & Air).
Do you suggest a way to do this?

[ping]

this is easy using a new threshold with the part surface you require forces measured on as the input part, the scalar field function set to the volume fraction of water or air, and the range 0,.5 or .5,1 depending on which field is chosen. this creates a new derived part which is a subset of the chosen input part and you do your force calcs on this new part

[ali_ebrahimi]

Originally Posted by ping

this is easy using a new threshold with the part surface you require forces measured on as the input part, the scalar field function set to the volume fraction of water or air, and the range 0,.5 or .5,1 depending on which field is chosen. this creates a new derived part which is a subset of the chosen input part and you do your force calcs on this new part

I have done these processes before and the answer was not correct.
However, the sum of the aerodynamic and hydrodynamic lift forces calculated from the threshold will not be equal to the total lift force calculated from the part region.
I share photos of the settings made.

[ping]

check the threshold parts in a geometry scene to make sure your threshold subsets of those surfaces are correct since it looks to me like you have used .05 instead of 0.5