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VSass December 6, 2012 06:34

Boundary Conditions on a Sphere

i want to apply a BC for velocity on a sphere. I want the velocity ALWAYS to be tangent on the faces of the sphere and never,during the solution, going through its surface.

Does anybody know which BC i should apply?

tomf December 7, 2012 04:42

Hello VSass,

It depends whether your sphere should be moving (movingMesh) or if it is only rotating in a stationary point. I am assuming it is the latter, in that case you can use:


If it is the former:


Depending on the choice you may need to set some other parameters that describe the motion.


VSass December 7, 2012 04:47

Thanks Tomf,

i have a fixed sphere so i guess i sould work with the rotatingWallVelocity.

Good day to you

Bernhard December 7, 2012 07:44

I am not sure what you are trying to model, but you could also consider slip as boundary condition.

VSass December 7, 2012 10:46


i have a hybrid sphere seperated in two boundaries, upstream and downstream, and this hybrid sphere is located inside a farfield which is also spherical and we suppose it is far away from our hybrid sphere. I am trying to solve the Navier - Stokes equations in the hybrid sphere using icoFoam,but Courant number keeps crashing no matter what time step i apply. I now work on modified icoFoam in order to keep e.g. maxCo=0.7,but i want to be sure that the crash is not due to boundary conditions.

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