A discussion on viscosity of liquids

Abstract

G. I. Taylor, F. R. S.—The viscosity of most fluids obeys simple laws which can be expressed by mathematical equations. Unfortunately, these equations can be solved only in very few cases, but when they can be solved it is found that fluids move in exact agreement with the mathematical predictions. This is now known to be true even in the case of turbulent motion, for a prediction based only on the law of viscosity has recently been made concerning the rate of decay of the energy of turbulent movement. This prediction has been verified experimentally. The difficulties which beset the mathematician who attempts to analyse turbulent flow are so great that some workers in the past have stated their belief that the law of viscosity does not apply in this case. They have even thought that there is an essential impossibility in analysing turbulent flow by means of the usual differential equations of motion for viscous fluids.