Numerical Investigation of the Characteristics and Interference Effect of Flow Past Multi-Cylinder at Low Reynolds Numbers

The flow around an staggered arrangement of seven cylinders is numerically studied using the finite element method to solve the two-dimensional and incompressible Navier—Stokes equations. The Reynolds number is 200 and the spacing ratios \(L{\text{/}}D\) = 1.1–5. In accordance with different hydrodynamic characteristics and vortex street arrangements, three distinct forms of wake flow can be identified, namely, the single bluff-body pattern (\(1.1 < L{\text{/}}D < 1.5\)), the deflected pattern (\(1.5 < L{\text{/}}D\) < 3), and the vortex impact pattern (\(3 < L{\text{/}}D < 5\)). For the further in-depth study of the characteristics of different wake patterns, the variations of the hydrodynamic forces on seven cylinders and the underlying mechanisms are analyzed and the wake structures are presented. The results of the analysis show that the gap flow under different wake patterns has different effects on the change of the hydrodynamic characteristics. It is found that the change of the wake structure is closely related to the change of the wake pattern.