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Abstract
Laminar natural and mixed convection heat transfer from an isothermal horizontal square cylinder was experimentally and numerically studied. The dimensionless mathematical models combined with the boundary conditions of the mentioned problem are derived based on the continuity, Navier-Stokes, and energy equations. The derived equations system was solved using a computer program based on Patanker technique algorithm [43]. The numerical solutions cover cases of natural and mixed convection for Prandtl number, Pr = 0.7. Two different values of the Grashof number, Gr were used. These values are 9.895 xl and 4.388 xl to match the experimental values. The effect of Ra on solution for an aspect ratio of 0.1 is also rçported. The results cover the same range of Reynolds number used in experimental study for assisting flow (P=0°) and opposing flow (‘l’ 180°) in the case of mixed convection.The local values of the Nusselt number distributed along the sides of the square cylinder and the average Nusselt number were calculated and plotted. Streamlines and
isotherms were also generated to describe the flow around the square cylinder.The experimental study includes designing and constructing the test rig to fulfill the research requirements. The mixed convection experiments were established for Grashof numbers from 9.895xl0 to 4.388xl0, Reynolds number ranging from 48 to 670, and the attack angles, ‘1’ from 0° to 180° with steps of 30°. The experimental results gave the average Nusselt number for air (Pr = 0.7).
Both numerical and experimental results were correlated. Comparisons between
present and published work related to this work show good agreement. However, the present correlations covered wide ranges of the variables.