Force library

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 May 22, 2013, 09:05 Force library #1 Member   Pengchuan Wang Join Date: Nov 2012 Location: Michigan USA Posts: 54 Rep Power: 4 Hello everyone, I'm new to OpenFOAM. I played with icoFoam and simpleFoam for a few months. Now I want to move to multi-phase flow, which is mixture of air and water, so I choose interFoam. Then comes the question. Originally I use the force library to calculate the torque and use patchIntegrate to calculate the volume flow rate in icoFoam and simpleFoam. And the viscosity of the single-phase flow is defined in transportProperties file. But now, it becomes multi-phase flow and the viscosity is a function of the phae fraction of the mixture, and the phase fraction is different everywhere. Then how can I calculate the "local viscosity" to calculate the force and torque on the wall? And how can I calculate the "pure" water flow rate at the boundaries. Thanks, Pengchuan

 May 22, 2013, 09:10 #2 Senior Member   Håkon Strandenes Join Date: Dec 2011 Location: Norway Posts: 111 Rep Power: 10 When it comes to calculating what you call the "pure water flow" (or the volume flux of one phase only) I think you should study these tutorials: https://www.hpc.ntnu.no/display/hpc/...llway+Tutorial https://www.hpc.ntnu.no/display/hpc/...AM+-+swak4Foam They describe in detail how to monitor flow of one phase, either in the domain or at a boundary.

May 22, 2013, 09:20
#3
Member

Pengchuan Wang
Join Date: Nov 2012
Location: Michigan USA
Posts: 54
Rep Power: 4
Hi Hakon,

Thank you for your quick reply, I'll work on that. Thanks again. Then do you have any idea on how to calculate the torque?

Quote:
 Originally Posted by haakon When it comes to calculating what you call the "pure water flow" (or the volume flux of one phase only) I think you should study these tutorials: https://www.hpc.ntnu.no/display/hpc/...llway+Tutorial https://www.hpc.ntnu.no/display/hpc/...AM+-+swak4Foam They describe in detail how to monitor flow of one phase, either in the domain or at a boundary.

 May 22, 2013, 09:28 #4 Senior Member   Håkon Strandenes Join Date: Dec 2011 Location: Norway Posts: 111 Rep Power: 10 No, not in multiphase flows at least. I know that in regular, single-phase flows the torque is calculated by the forces and forceCoeffs function objects. You specify the axis around which to calculate the torque with the CofR vector. But again, I am very uncertain on how to do this for multiphase flows.

 Tags force library, patchintegrate, torque

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