Numerical simulations of flow field and flow-induced vibration in rectangular channel with single cylinder

Abstract

A vortex street structure in a narrow channel can not only enhance the mixing efficiency of the turbulence, but also cause flow-induced vibration. In this study, a rectangular channel with a single cylinder was used as the research object. The generation and influence factors of the turbulent vortex street structure in the channel and the flow-induced vibration of a cylindrical structure caused by the vortex street structure were numerically studied. First, based on the experimental data and numerical results, the accuracy of the numerical method used in this study for the flow field calculation and fluid–structure coupling calculation was verified. Second, the influence of the rod–wall gap size (W/D) on the vortex street structure formation and turbulent mixing efficiency was studied based on the validated numerical method. Finally, the flow-induced vibration of a cylindrical structure caused by a vortex street structure in a narrow channel was numerically studied using a weak coupling algorithm, and the influence of W/D on the vibration characteristics of the cylindrical structure was obtained. The results showed that an RSM-ε anisotropic turbulence model could accurately capture the vortex street in a narrow channel. The value of W/D had a significant effect on the formation of the vortex street structure. When W/D is greater than 1.150, the vortex street structure disappears. The presence of vortex street structure can significantly enhance the mixing efficiency of turbulent flow. The vortex street structure also caused the buckling of the cylinder in the normal direction of the narrow channel.