Hello All,

Can anyone help me with setting up a flow problem in a pipe for a non-newtonian fluid (e.g. with a yield stress). Any tutorial will be appreciated.

Regards,

Naveed.

[meroney]

For laminar flow in Fluent: Choose Laminar turbulence model in viscosity, select liquid water in materials, change name, use drop down menu under viscosity and select non-Newtonian model you desire: power law, Carreau, Herschel-Buckley, or Cross model. Calculate.

For turbulent flow in Fluent: First select a turbulence model (ke, ke realizable, etc.), then use text command to go through menus as follows:
/define/models/viscous/turbulent-expert then answer yes to enable turbulence for non-Newtonian fluids
Now select a liquid material and the non-Newtonian options will appear under the viscous property listing. Calculate.

There has been very little published using the non-Newtonian turbulence options; hence, there is no assurance that the model results are actually realistic! I suggest doing some validation for yourself on pipe flow, jets, or wall layers.