Time-dependent viscosity implementation in fluent

ComputerGuy · January 27, 2010, 23:18

Does anyone have an example (UDF/literature link?), or know if this is possible to do in fluent? Can one model thixotropy or rheopexy (rheopecty) in this program? I realize it will be a UDF implementation, but I'm unable to see how I would track parcels of fluid to monitor their shear rate vs. time, as thixotropic fluids have age-dependent viscosity.

Could this be implemented by injecting neutrally buoyant, very tiny particles and monitoring their shear vs time, and adjusting the viscosity of the fluid volume which contains them?

Thanks for you help.

Agustin · April 19, 2010, 11:31

You can use the croos model , if you know the coeficients of the equation, you can create a new component in Define-Materials and viscosity, you select the croos model and you only have to introduce the parameters of the model.
In the tutorial of fluent 2007, the tutorial number 8 talk about the non-Newtonian transitional flow in an eccentric annulus, you can find this in google.
I don't know if you ask about it, but it is the only thing that I know.

Sorry for open an old topic.

moisedion · September 20, 2011, 04:11

I'm curious to know how you did solve this time dependent rheological Simulation... Was it by UDF or by creating a Solver in OpenFoam? Also, Cross Model is not for Time dependency but Shear Rate Dependency (thinning)...

January 27, 2010, 23:18	Time-dependent viscosity implementation in fluent	#1
ComputerGuy Senior Member Real Name :) Join Date: Jan 2010 Location: United States Posts: 192 Rep Power: 16	Does anyone have an example (UDF/literature link?), or know if this is possible to do in fluent? Can one model thixotropy or rheopexy (rheopecty) in this program? I realize it will be a UDF implementation, but I'm unable to see how I would track parcels of fluid to monitor their shear rate vs. time, as thixotropic fluids have age-dependent viscosity. Could this be implemented by injecting neutrally buoyant, very tiny particles and monitoring their shear vs time, and adjusting the viscosity of the fluid volume which contains them? Thanks for you help.

September 20, 2011, 04:11		#3
moisedion New Member MOISE DION Join Date: Sep 2011 Posts: 8 Rep Power: 15	I'm curious to know how you did solve this time dependent rheological Simulation... Was it by UDF or by creating a Solver in OpenFoam? Also, Cross Model is not for Time dependency but Shear Rate Dependency (thinning)... Last edited by moisedion; September 23, 2011 at 06:00. Reason: Provide further details

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April 19, 2010, 11:31		#2
Agustin New Member Agustin Join Date: Apr 2010 Posts: 1 Rep Power: 0	You can use the croos model , if you know the coeficients of the equation, you can create a new component in Define-Materials and viscosity, you select the croos model and you only have to introduce the parameters of the model. In the tutorial of fluent 2007, the tutorial number 8 talk about the non-Newtonian transitional flow in an eccentric annulus, you can find this in google. I don't know if you ask about it, but it is the only thing that I know. Sorry for open an old topic.