Abstract
Numerical fluid flow and heat transfer results were obtained for a pulsed laminar flow through a vertical, isothermal-walled tube for Gr/Re = 0 (no buoyancy) and 30 (buoyancy) at a cyclic-averaged Reynolds number of 5 x 10 2 . The pulsations resulted in cyclic-averaged Nusselt numbers Nu av that were greater than the steady, fully developed laminar Nusselt number, with Nu av increasing with increasing frequency. The Nusselt number also increased with increasing amplitude a for Gr/Re - 0, but it remained virtually constant beyond a - 0.1 for Gr/Re - 30. Although the NV av values at Gr/Re - 30 were greater than at Gr/Re = 0, they were offset by relatively large values of the cyclic-averaged dimensionless wall shear stress τ av , For Gr/Re = 30, Nu av /τ av was either the same or less than that for steady, fully developed laminar flow. Conversely, Nu av /τ av increased by as much as 39% for Gr/Re = 0.
Published Version
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