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-   -   fluent's "outflow" BC not compatible with Singhal cavitation model? (

aditya.pandare January 31, 2013 01:26

fluent's "outflow" BC not compatible with Singhal cavitation model?
I am simulating a cavitating flow in fluent 14.5 and trying to use the Singhal et al cavitation model for the same.
Due to the peculiar flow conditions, I have to use the "outflow" BC at the outlet.
but when I try to run the Singhal model with outflow, it gives 2 errors:
1. outflow cannot be used with cavitation model
2. divergence detected in AMG solver ( all the eqns: k, e, x,y,z momentum, pressure correction)

but I can run the same simulation with Schnerr-sauer cavitation model

so is it the case that only the Singhal cavitation model is not compatible with "outflow"? or is there something wrong with my case setup?

any help will be useful!
thank you

sarodesr October 24, 2013 08:27


Just wondering how did you use Singhal Model in fluent v 14.5. As per my observation, in cavitation model only two models are shown by fluent 1) Schnerr-sauer 2) Zwart-geber-Blmari.
I tried to search but didn't find. Did you write UDF/UDS for the same.


Kokemoor October 24, 2013 10:16

My limited experience with the Singhal et al model found it to be very unstable and sensitive to mesh and initialization. It may simply take some patience and experimentation to find the right conditions for convergence.

I'm not sure why your outflow condition might work with Schnerr-Sauer. The Fluent User's Guide says under 6.3.10 that outflow can't be used with any multiphase models (presumably because the mass balance correction doesn't work with multiple phases).

aditya.pandare October 24, 2013 13:16

Sarang, after you select the Multiphase model in the models tab, use "solve/set/expert" in the text command window. enable the Singhal cavitation model.

Kokemoor, yes you are right. actually I found this out long back, but forgot to update here; thanks anyways. :)

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