Buoyancy Driven Exchange Flow in a Horizontal Pipe

The paper describes a theoretical and experimental study of steady exchange flow in a horizontal pipe that connects to regions containing fluids of differing densities. The exchange flow rate for an inviscid fluid is controlled by the diameter of the connecting pipe and the densities of the fluids. Viscosity causes a reduction in the rate of exchange and the extent of this change is investigated using an approximately equivalent flow, field to describe the boundary layer development in the exchange pipe. In laminar flow the normalized exchange flow rate can be expressed in terms of a single parameter involving the length to diameter ratio of the connecting pipe and the Reynolds number of the pipe flow.