Viscosity of water

Abstract

Water is the primary standard of viscosity. Hence measurement of its viscosity has been discussed in detail. The work carried out at NBS (NIST) USA has been described. Swindells capillary viscometer has been described in detail. Swindells measured the viscosity of water by measuring the pressure difference between the ends of a capillary for a known rate of flow. The pioneer works of Roscoe and Bainbridge, Torklep and Oye, Kestin and Shankland and Berstad et al. along with the estimated uncertainty, have been described in detail. Kestin and Shankland arrived at the uncertainty value by taking the sum of component uncertainties and got the value 0.26%. A small comment about this method has been offered. A shortcoming of not taking into considering uncertainty calculated by type B method has also been pointed out. Overall review by Bauer et al. of PTB has been given. Viscosity temperature relationship has been discussed. Viscosity of various oils used as standards at various temperatures has been given. Dependence of viscosity of water on pressure is quite weak. So only a viscosity coefficient with respect to pressure has been indicated.