The flow interference investigation of multi-square prisms under fluid-structure interaction. I. Proximal wake characteristics of tandem square prisms

Abstract

This study investigates the aerodynamic characteristics and interference effect of tandem square prisms in fluid–structure interaction. Using large eddy simulation, three-dimensional tandem square prisms are analyzed under different spacing and vibration. Based on the mean pressure coefficient and flow field phenomenology, the specific reasons and underlying mechanisms of the changes are discussed. The results show that the structural vibration accelerates the curling of the shear layer around the upstream structure, increases the vortex shedding frequency of the structure, and reduces the distance between the vortices. It also amplifies the transverse correlation between vortex structures and intensifies the influence of the gap flow on the downstream structure. The increased spacing between the tandem square prisms changes the flow mechanism of the wake separated from the upstream structure, leading to a more uniform and regular streamlined pattern. Simultaneously, a flow field phenomenon is observed, such as an early rolled-up shear layer, turbulence enhancement, preliminary vortex formation, weakened downwash flow, and the change of field flow due to the vibration. This study is expected to deepen the understanding of flow interference investigation between tandem square prisms in the fluid–structure interaction field.