Power Law Model
The power law model is a common rheological model to quantify (typically) the shear thinning nature of a sample, with the value closer to zero indicating a more shear thinning material.
It can be used to describe any material that shows power law behavior which is a proportional response of stress to shear rate (or linear plot of viscosity vs shear rate). Technically, a power law index, n>1 denotes that the sample is shear thickening; n<1 denotes that the sample is shear thinning and n=1 shows a Newtonian, viscous behaviour.
Note: do not use this model on data areas that show plateaus, i.e., the zero shear and infinite shear viscosities.