Experimental and numerical investigation of flow around spheres

The aim of the present study was to investigate the flow characteristics around single and dual spheres in three different locations with respect to flow condition. Initially the single sphere was positioned in the free-stream flow to observe the flow characteristics for the purpose of comparisons. Effects of the free-surface flow on the flow structures downstream of the single sphere were investigated for four different submerging elevations. Interaction between laminar boundary layer and wake flow downstream of the single sphere was also studied using four different embedding elevations of the sphere from the plain plate. On the other hand, flow structures around two spheres with tandem arrangement were studies. Here, four different separation distances were conducted between spheres. Secondly, experiments and computations were performed on the side-by-side spheres with different separation distances between spheres. Finally, flow characteristics around the segregated spheres were investigated using three different separation distances and three different separation angles. All investigated cases associated with the single sphere and dual spheres were performed at the Reynolds number of 5,000 with respect to the free-stream velocity and sphere diameter. In addition, for calculation of the turbulence characteristics, Large Eddy Simulation using a dynamic Smagorinsky sub-grid scale was used and experiments were performed using the Particle Image Velocimetry technique. The interaction between the free surface and wake flow increases by decreasing the submerging elevation. Finally, the obtained results revealed that interaction between the spheres varies as a function of arrangement of spheres.