Experiments with rotating fluids

Abstract It is well known that predictions about fluid motion based on the classic hydrodynamical theory are seldom verified in experiments performed with actual fluids. The explanation of this want of agreement between theory and experiment is to be found chiefly in the conditions at the surfaces of the solid boundaries of the fluid. The classical hydrodynamical theory assumes that perfect slipping takes place, whereas in actual fluids the surface layers of the fluid are churned up into eddies. In the case of motions which depend on the conditions at the surface, therefore, no agreement is to be expected between theory and experiment. This class of fluid motion,unfortunately, includes all cases where a solid moves through a fluid which is otherwise at rest.