Wake-Induced Vibration of Flexible Splitter Plate Attached to Rear Point of Circular Cylinder
In this paper,the flow past a flexible splitter plate attached behind a rigid circular cylinder is numerically investigated at a low Reynolds number of 160.As a two-way Fluid-Structure Interaction(FSI)issue,the simulation is conducted using the preCICE open source coupling library with OpenFOAM-9 and deal.ii as the fluid domain and solid domain solving modules,respectively.The finite-volume method(FVM)and finite-element method(FEM)are utilized to solve fluid and solid motion equations,respectively.The effects of the plate length(L/D=2.0-4.0)and non-dimensional Young's modulus(E*=100-5 000)on the vibration response and flow structure are systematically examined.Numerical results indicate that the vibration response of the flexible plate depends on both L/D and E*.The boundary layer separated from the surface of the cylinder curls behind the cylinder,and migrates along the surface of the splitter plate,forming low-pressure areas that cause periodic deformation of the flexible splitter plate.Finally,the shear layer is cut off by the plate tip and hence the formation of the vortex.As the plate length increases,the number of local vortices appearing along the surface of the splitter plate increases,contributing to the higher-order vibration response.According to the vibration order and whether there is bifurcation phenomenon(symmetry breaking),five vibration modes are identified:symmetry-Ⅰ,symmetry-Ⅱ,symmetry-Ⅲ,bifurcation-Ⅰ and bifurcation-Ⅱ mode,respectively.Bifurcation,as a transitional mode between the symmetry-Ⅰ and symmetry-Ⅱ,has a sudden decrease in the vibration amplitude.Compared to a bare cylinder,the flexible splitter plate within a certain stiffness range reduces the drag and vortex shedding frequency of the overall structure,but their suppression effect is weaker than that of the rigid plate within the stiffness range studied.
Fluid-structure interactionFlexible splitter plateVibration modePassive control
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