Variable viscosity effect on the laminar water boundary layer on heated cones

A physical model is chosen which is a semiinfinite axisymmetric cone whose axis of generation is aligned parallel to a uniform flow and normal to the direction of gravity. The similarity solution of a flow past the cone, heated at a constant temperature higher than the free-stream temperature, describes clearly the development of the three-dimensional conical boundary-layer flow. The effects of the cone angle and the temperature-dependent viscosity of water on the flow are studied along with the relative importance of the crossflow and the variable viscosity on the shear stress distribution and on the heat transfer. It is shown that for a cone of small cone angle, the importance of thermally induced crossflow grows as the fluid flows downstream. For a cone of large cone angle, the crossflow effect is only important in the neighborhood of the cone vertex where the magnitude of tha axial-flow velocity is small and has an inflection point for a possible early flow transition.