# solving for forces using compressibleInterFoam

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 July 15, 2014, 21:56 solving for forces using compressibleInterFoam #1 New Member   Betsy Join Date: Jul 2014 Location: Honolulu, HI Posts: 5 Rep Power: 10 Hello, I am trying to solve for forces on a simple model using a modified version of compressibleInterFoam to apply the waves2Foam toolbox. I also set my viscosity to near-zero so that I am solving Euler's equations. I have been comparing these results with the exact same mesh, boundary conditions, etc. but solving the incompressible case using interFoam. I am having trouble getting accurate forces on my model using the compressible solver (horizontal is much larger) and there seems to be limited publications where people have used this solver and have said what they used for psi, pmin and their boundary conditions. Can anyone help point out some publications? A few things I have noticed so far (please correct me if I am wrong): 1) pmin must be set to 100000 (atmospheric pressure) in order for rho to be correct (in the tutorial depthCharge2D it is set as pmin = 10000) 2) pressure is output only as dynamic pressure (p_rgh), not total pressure (p) as in other solvers, for example, interFoam 3) for pressure boundary conditions at a wall, I have to use buoyantPressure, otherwise pressure will not be calculated on the body, only the internal field. 4) for air, I use psi = 1e-5 which is the compressiblilty of air (in this case, psi = 1/RT = 1/(286.9*293.15) = 1e-5. Is there anything else I am missing? I appreciate any advice or suggestions of publications. Thank you! Betsy

 July 17, 2014, 00:50 #2 New Member   Betsy Join Date: Jul 2014 Location: Honolulu, HI Posts: 5 Rep Power: 10 Ok, upon further research I realize that I was trying to solve for gauge pressure and I need to be solving for absolute pressure. So now my problem becomes, how to set the pressure field to absolute pressure using waves2Foam...

 March 7, 2023, 08:06 #3 New Member   Tommaso Join Date: Jan 2020 Posts: 16 Rep Power: 5 Any updates on this?

 Tags compressible solver, compressibleinterfoam, forces, openfoam, waves2foam