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billynoe April 11, 2011 10:22

Boundary conditions for a fan simulation
Hello all,
I am trying to run a simulation with of a fan. Instead of using a dynamic mesh I wanted to do this using two boundaries to simulate a fan. I set the output side of the fan as a constant velocity and the inlet side as a zero pressure. outlet side zerogradient pressure and inlet side zerogradient velocity. This is probably why my sim keeps crashing. I would appreciate any ideas because I'm all out. I have tried several other BC's without success. The reason I don't want to do dymfoam is because I have almost zero cpu and I'm in 2D.

billynoe April 11, 2011 11:24

I'm thinking fan BC might be good, but gmshtofoam will not allow me to make a patch that has no outside surfaces :confused:

Sylvain August 18, 2011 11:38


You can either use the fan BC or fanPressure BC

-fan BC: -pressure jump through an interface. The interface is created with the createbaffle utility. see pimpleFoam/TjunctionFan tutorial to see how to make it

-you have two distinct patches which model the inlet and outlet of a fan. the total pressure prescribed is calculated from a fan curve model.

I'm not yet confident with the last one. i made some comparisons between the two of them, and it looks ok, but i'm not sure what the fanPressure BC is exactly doing.


Toorop June 1, 2012 10:58

2 Attachment(s)

I have successfully created a fan boundary in the cavity case. I have tested it with icoFoam solver, everything seems OK - cavityFan.

I would like to use the buoyantBoussinesqPimpleFoam solver with the same setup, but the fan has no effect - cavityBuoyantFan. I guess the problem is that there in no p equation, so the fan is not doing anything.

Any idea how to get the fan boundary with buoyantBoussinesqPimpleFoam? Thanks!

soonic July 8, 2013 04:06

did you already succeed in using fan BC with buoyant solvers ? I am interested in solution.

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