Effects of Buoyancy on Heat Transfer on Circular Staggered Cylinders

Incompressible flow around a pair of circular cylinders in various staggered arrangements with heated upstream cylinder is investigated in this study. Three dimensional direct numerical simulation (DNS) has been performed with spatial discretization based on the spectral/hp element method with the Reynolds numbers of 200 and the Richardson numbers are varied from 0.05 to 2.0. The longitudinal separation to cylinders diameter ratio is set to 2.5 and 5.0 with transverse separation to cylinders diameter ratio is fixed at 1.0. The investigation focuses on the effects of buoyancy as well as cylinders placement on both flow structures and local heat transfer characteristics of both cylinders.