Herschel–Bulkley fluid

A Herschel–Bulkley fluid is a type of non-Newtonian fluid that exhibits both yield stress and shear-thinning (or shear-thickening) behavior. The defining characteristic of such fluids is that they do not begin to flow until a certain threshold stress, known as the yield stress, is exceeded. Once this yield stress is surpassed, the fluid flows according to a power-law relationship that describes its viscosity.