Hye all, hope all of you doing fine today.
In my case for viscosity that dependent on temperature case, supposedly I need to tick the energy equation and laminar-viscous heating, unfortunately, the simulation will be faced with an error. But when I untick the viscous heating the system can be run and get the simulation result. As per attachment location for energy and laminar-viscous in ANSYS FLUENT, my UDF for viscosity dependent temperature case and error that appears when i tick the viscous heating.Thanks..any idea guys?
Hello Zuraidah Rasep ,
do you have a temperature differences in your case, if you do not select the viscous heating? Your µ-T equation from the UDF changes the viscosity very strongly, around two orders of magnitude for a100K range, this will destabilize the iterative solvers of the CFD software. This µ-T equation seems to be a very rough guess at least over a broad temperature range, therefore you should limit it to a temperature range where it is valid for the assumed fluid.
Furthermore, you can try smaller under relaxation factors for the energy terms or artificially limiting the temperature to stabilize the solver.
Best regards
Christian
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