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Souviktor April 3, 2009 08:09

custom pressure field at the faces
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I am simulating a configuration with high non linear body force using udf.Obviously fluent stores this body force at the cell center.So during calculation of velocity if the body force is needed at the cell face it has to interpolate by whatever scheme.But the body force is so nonlinear that it incorporates large error.
I have hand written code that solves this issue by adding a part of body force(the highly non linear part which varies only spatially) to the pressure and defining pressure and velocity in a staggered way.there I have two types of cells ,scalar and vector.scalars(pressure ,density,temperature) are defined at the scalar cell center and vectors(velocity)are defined at the vector cell center.the face of a scalar cell is center of the vector cell.(please see the attachment)

So essentially I define pressure (with a part of body force added to it) at the scalar cell center and velocity is computed by using pressure at its two faces.

Fluent on the contrary uses collocated scheme which means defining pressure and velocity at the same point.

In fluent how can I at all achieve this?can I use define_adjust udf to manually set the pressure prior to each iteration?

any suggestion is greatly appreciated ..please pardon me if I am making any fundamental mistake in understanding and describing the situation!

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