Mixed convective vertically upward flow past side-by-side square cylinders at incidence

Fluid dynamics and heat transfer behaviour are studied past side-by-side square cylinders at incidence in vertical flow arrangement numerically considering laminar, Newtonian, steady, incompressible and two-dimensional flow using Finite Volume Method based ANSYS Fluent solver. Using air (Pr = 0.7) as the working fluid, computations are performed at a representative value of Re = 100. The angle of incidence (α) is varied from 0° to 45° in the step of 5°, whereas, the lateral distance between the cylinders is kept constant. To consider all possibilities, cylinders are rotated either clockwise or counter-clockwise, simultaneously or individually, which generates thirty-four different orientations. Buoyancy assisting phenomenon is created by changing the Richardson number (Ri) from 0 to 1 in step of 0.25. Due to the variation of the angle of incidence and its orientations, vortex generation is observed in the buoyancy assisting case at a critical value of Ri. To study heat transfer characteristics, time average and the local Nusselt number are analysed. For a fixed lateral distance between the cylinders, maximum heat transfer is found to occur at an incident angle of 45°. Other important parameters, such as drag coefficient (CD), lift coefficient (CL), Strouhal number (St) are also studied.