How to implement bulk viscosity in Navier stokes eqn using UDF? -- CFD Online Discussion Forums

June 26, 2022, 07:02

How to implement bulk viscosity in Navier stokes eqn using UDF?

Siba11

Member

Odisha

Join Date: Jan 2020

Posts: 59

Rep Power: 6

Hello everyone,
I'm trying to implement the bulk viscosity term in the X-momentum equation using a UDF in FLUENT.
From my understanding of the UDF manual, the best way to go about it is to model the bulk-viscosity term as a "source" term.
So I worked out the source term and wrote a small code for it (please find the attached PDF for the code.)

I then started FLUENT and compiled my UDF. It showed no errors.

However, when I start the calculation, the 'continuity' & 'X-velocity' residuals blow up and the calculation stops. This means there's some problem with the code or my source term.
I will appreciate any help on this matter.

Sincerely,
Sibasish

Attached Files

Source_term UDF.pdf (127.4 KB, 13 views)

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