Structural Viscosity

the viscosity related to the appearance of a structure in a liquid and dependent on the gradient of the flow rate. Structural viscosity is typical of disperse systems, including colloidal solutions, and solutions of high polymers. Structural viscosity arises in these systems because in the flow of a structuralized liquid the work done by external forces is expended not only in overcoming true (Newtonian) viscosity but also in destroying the structure and reorienting the elongated particles in the flow. Structural viscosity plays a large role in transferring disperse systems, for example, slurries when dredging river channels, and liquid polymers through pipes and in the flow of these substances through the apparatus used in the chemical industry. The term “structural viscosity” was introduced in 1925 by the German scientist W. Ostwald.