The flow behavior index (n) is a parameter in the power law model that characterizes the flow behavior of non-Newtonian fluids, indicating whether the fluid is shear-thinning or shear-thickening. A flow behavior index less than 1 indicates shear-thinning behavior, equal to 1 indicates Newtonian behavior, and greater than 1 indicates shear-thickening behavior.
Shear-thinning is a non-Newtonian behavior where a fluid's viscosity decreases with increasing shear rate, allowing it to flow more easily under force. This property is crucial in various applications like food processing, cosmetics, and pharmaceuticals, where ease of flow is needed without compromising structural integrity at rest.