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 ashishraval April 28, 2004 06:11

Can We Model Spherical Symmetry in CFX

Dear All, I have one query regarding spherical symmetry...e.g.consider Bomb Geometry. It essentially expands as sphere. Now does CFX has the capability of applying spherically Symmetrical Boundary conditions ? and solving it ? or can we model Sphere in CFX and essentially solve them? I will appreciate your contributions on it.. Thank you for cooperation. Sincerely, Ashish

 Glenn Horrocks April 28, 2004 18:36

Re: Can We Model Spherical Symmetry in CFX

Hi Ashish,

CFX does not directly support spherical 1D simulations, and for the record it does not directly support 2D simulations either, as the solver always solves 3 velocity equations even if one or more of the equations is always zero.

Can make it do 2D and 1D simulation by generating a mesh with only one element thickness in any dimensions not modelled (that would mean your 1D simulation is just a line of elements, one element thick), with symmetry planes on both sides. Note that the solver will still solve all three velocity components, but only one or two of these components will be non-zero in the converged solution (assuming you have lined your model up with the coordinate axis).

For your spherical 1D simulation you would need to make the line of elements wedge shaped, that is tapering down to a singularity at the origin.

It is possible to generate these types of grids with CFX-Build and CFX-Mesh, but they can only mesh with tets and prisms so is not really suitable. Your best bet is to use ICEM CFD 4.CFX and extrude the meshes in the single element thick directions.

Regards, Glenn