Fascinating polymeric liquids

Abstract

Fluid dynamics is an old subject. In 1687, Isaac Newton wrote a simple equation defining the viscosity of a fluid as the coefficient of proportionality between the shear stress and the velocity gradient. Newton's equation does well at describing gases and liquids made up of “light” molecules—those of molecular weight less than about 1000. By the middle of the last century the mathematical description of the flow of such “Newtonian” fluids was well established. This description is based on use of the laws of conservation of mass and momentum.