Author Topic: Fluid with a non-Newtonian viscosity dependence in CFX.  (Read 8694 times)

Offline pitney1

  • Jr. Member
  • **
  • Posts: 65
  • Reputation: +0/-0
  • Searching for solution
    • View Profile
I would like to set-up a problem for a fluid with a non-Newtonian viscosity dependence. Are there any built in models for doing this in CFX?

Offline william

  • Full Member
  • ***
  • Posts: 159
  • Reputation: +15/-0
  • Know it, share it.
    • View Profile
Re: Fluid with a non-Newtonian viscosity dependence in CFX.
« Reply #1 on: May 11, 2012, 10:47:51 PM »
There are various non-Newtonian viscosity models available in CFX as beta features.
The available models are the Herschel-Bulkley, Bird-Carreau, Cross, and Power-Law
models. The Bingham Plastic model can be set up as a special case of the Herschel-Bulkley

To enable access to the models, you can modify the RULES file located in the /etc folder
of the CFX installation directory as follows.

1. First copy the existing RULES file to another file (say RULES.OLD) so that the original file is preserved.
2. Edit the RULEs file and find the object:


Replace the entire SINGLETON: DYNAMIC VISCOSITY object with the corresponding object contained
in the attached file short_rules.

3. Save the modified RULES file and start the CFX launcher. If you edit an existing definition file
using the Solver Manager, you will be able to change the Option for Dynamic Viscosity for a particular material
to one of the non-Newtonian options. You must then add and set the desired parameters for that
particular model.