BUOYANCY EFFECTS ON FORCED-CONVECTION FROM A HORIZONTAL CYLINDER IN ACROSS-FLOW

An experimental investigation of buoyancy effects on forced convection heat transfer from a horizontal cylinder dissipating a uniform heat f lux was conducted. An open-loop wind tunnel was used to provide crossf low over the cylinder. The heat flux for the 4.45-cm-diam, 38-cm-long cylinder was varied between 10-250 W, and the flow velocities were var ied from 1.4 to 8 m/s. This resulted in Reynolds number and modified G rashof number values in the ranges of 3.2 x 10(-3) to 2.13 x 10(4), an d 2.8 x 10(6) to 5.7 x 10(7), respectively. The local Nusselt number i s correlated as a function of the Reynolds and modified Grashof number s. The average Nusselt numbers from the present results in the forced and mixed convection regimes are also correlated. These correlations a re also compared with the available correlations in literature.