Power-law fluid

A power-law fluid is a simplified model for the behavior of non-Newtonian fluids in which the shear stress is proportional to the shear rate raised to a power. The model captures shear thinning when the power is less than one and shear thickening when the power is greater than one. Though it cannot describe the full deformation history dependence of real complex fluids, the power-law model provides a tractable entry point for engineering analysis and theoretical exploration of flows where viscosity itself is a function of the deformation rate. The model's simplicity makes it valuable for dimensional analysis and scaling arguments, even when more sophisticated rheological models are ultimately required for quantitative prediction.