Viscosity.

An adequate knowledge of viscosity plays a very important role in a variety of interesting engineering problems involving fluid flow and momentum transfer. This much-needed information is scattered throughout the literature, for a limited number of materials, either as obtained from an experimental measurement or as values computed according to a certain theoretical procedure. The probability of finding even an approximate value of viscosity decreases considerably as the molecular complexity of the material increases and/or the interest shifts toward extremes in such environmental conditions as temperatures, density, magnetic fields, electric fields, etc. The information available for multicomponent systems is meager in comparison with that for pure substances, and in general the theoretical understanding of the phenomenon is less developed for the liquid state than for the gaseous state. Measurements of the viscosity of liquids and their mixtures are quite scarce. In the absence of elaborate experimental information and adequate theoretical understanding of the coefficient of viscosity for fluids and their mixtures, it would be most desirable to critically evaluate the available information and by a judicious interplay of theory and experiment develop, as well as possible, both the standard data and reliable procedures for theoretical calculations. In the first part the present state of the art theory, estimation, and measurement techniques of gases and gas mixtures, and then of liquids and liquid mixtures is reviewed. The second part deals with the critical evaluation of viscosity data obtained by different workers and different techniques, and lists the recommended values for pure and mixed materials in the gaseous and liquid states. In this entire volume by the word fluid is implied its traditional meaning, the gaseous and liquid states. (from paper)