Modeling Herschel-Bulkey Model

Ishan

Hi guys, I am trying to model Herschel-Bulkey Model in fluent. [Specifically Bingham Plastic whose shear stress - rate relation is given by: τ = τo + ηÏ� where τ is the shear stress

τo is the yield stress

η is the apparent viscosity

� is the shear rate ]

In fluent [Define > Materials> Viscosity> Herschel Bulkey] the input parameters for the apparent viscosity involves the following defination:

η = (τo + K [ Ï� â€" (τo/ µo)])/ Ï� where k is the consistency factor

µo is the yielding viscosity

As you can see it is a function of the shear rate. However I want to have a constant value for my apparent viscosity.

How can I do it?