COMPUTATIONAL SIMULATION AND EXPERIMENTAL VALIDATION OF DOUBLE SQUARE CYLINDERS FLOW IN STAGGERED ARRANGEMENT

Experimental and numerical study of the flow field around two finite square cylinders in staggered arrangement is the objective of the present work. Two similar cylinders having the same square cross-section of 50 mm x 50 mm with blockage ratio of 16.7% were considered in different arrangements. The staggered arrangement with different angular positions was considered. The turbulent incompressible Navier-Stokes equations are solved numerically using finite element method. The static pressure distributions on the two-cylinder surfaces were estimated and measured in all cases with different apart-distances between the two cylinders and consequently the pressure coefficient variations were calculated. In addition, the experiments were developed for three Reynolds numbers of 13.5, 9.5 and 6.8x104 (based on the cylinder side length) to investigate their effect on the turbulent flow. The upstream cylinder is not affected greatly for different angular positions and apart-distances. This effect is significant in the case of side-by-side, where the flow stream equally affects the two cylinders. Up to four cylinder-widths apart-distance, the upstream cylinder affects the downstream cylinder. The effect is changed from maximum value in tandem arrangement to minimum one for the case of side-by-side configuration. Moreover, where the upstream side of the downstream cylinder is affected by changing the Reynolds number, the other sides do not vary. The highest considered Reynolds number produces the lowest drag and side force coefficient. On the other hand, the computational results are in close agreement with the measured ones. The numerical visualization presents clearly the flow behavior around the cylinders and was validated by the measured and published data.