How to calculate total force?
 

when I finished the case "cavity" using the solver icoFoam, the pressure and velocity distribution are all known. That's to say, the pressure acting on movingWall is also computed. However, how do we sample these pressure value on movingWall and calculate the total force?

Thanks for help.

Take a look at the functionObjects in OpenFOAM. I think the motorBike tutorial uses the forceCoeffs function, as an example.

Thanks. It is really useful to calculate the total forces on a face.