Buoyancy in developed laminar curved tube flows (Q1059495)

The influence of buoyancy on fully developed laminar flow in curved tubes of circular cross-section is studied numerically. Steady flow for a constant property fluid, in terms of the Boussinesq approximation, is assumed. The thermal boundary conditions are specified as axially uniform heat flux and peripherally uniform wall temperature. The problem is solved using coarse, unequally spaced grids. The solutions cover a wide range of Prandtl, Dean and Grashof numbers and include the curvature ratio as an explicit parameter. The results are compared with results from the literature and reveal considerable differences. The buoyancy acts to increase the average Nusselt number, change the local Nusselt number distribution around the periphery, and rotate the orientation of the secondary flow.