The Use of Doubly Refracting Solutions in the Investigation of Fluid Flow Phenomena

摘要

The feasibility of using doubly refracting liquids for qualitative and quantitative flow studies is discussed. Of the many liquids which have the property of streaming double refraction, colloidal solutions of bentonite are most suitable because of their high sensitivity, low viscosity, cheapness, and comparative ease of preparation. The problems involved in the preparation and handling of bentonite solutions and the physical factors affecting the double refracting properties of bentonite, such as concentration, particle size, and temperature are investigated. An outline of the essential optical theory and of the application of double refraction methods in photoelasticity is presented. The methods of generating and measuring double refraction are described and an optical setup suitable for hydrodynamic studies is recommended. A thorough survey of existing literature concerning streaming double refraction for colloidal solutions and pure liquids is made. This includes the hydrodynamic theories developed. A method of determining the velocity distribution and streamlines for two-dimensional laminar flow utilizing ideas obtained from the literature is suggested. However, the adequacy of the hydrodynamic theory as applied to colloidal particles in twodimensional flow is open to question. Therefore a more complete analysis is attempted. These results indicate the need for special experiments in order to determine the proper relationships between double refraction and velocity gradients. A method for determining the velocity distribution and streamlines using pure liquids possessing birefringent properties is also presented. (Author)