Flux Enhancement By Shear Free Surfaces In A Turbulent Convection

Abstract In this Paper we will be dealing with turbulent natural convection in a long vertical pipe in which the flow is generated because of an unstable density difference across the two ends of the pipe. We create the density difference across the pipe using fresh water and brine. Since the density of brine is greater than that of fresh water it tries to settle down while the fresh water tries to fill up the upper space. This creates collision of fluid masses in the pipe leading to a turbulent flow at high levels of density differences. We will study the flow and its effect in the mid section of the pipe. Since water is an incompressible fluid because of the density difference the mass of fluid that goes up is equal to the mass of the fluid going down. Thus at any instant of time the net flow will be zero at any cross section of the pipe. Since the length to diameter ratio Ld ratio of the pipe is around 9 to 10 the flow will be axially homogeneous. Thus we have an axially homogenous flow with zero mean velocity and which is purely buoyancy driven. This is the basic flow for our experiments.