Computational study of the Effect of Structural Viscoelasticity on two-dimensional Fluid-Structure Interaction Problems

Fluid-solid interaction (FSI) of both viscoelastic structures and structures subject to viscoelastic support was studied numerically using the spectral-element and immersedboundary methods. Broadly two classes of FSI problems were investigated: (a) Vortexinduced vibration of the circular cylinder on a viscoelastic support, and (b) flow-induced deformation (FID) of the thin viscoelastic plate. Standard Linear Solid (SLS) model used for modelling viscoelastic material. Viscoelastic material, unlike elastic material, has an elastic as well as viscous character when undergoing deformation. The VIV and FID shows the non-monotonic variation of vibration amplitude response with damping. The response of the cylinder for nonlinear viscoelastic support was also studied. The equivalent reduced velocity, a measure of nonlinearity, is affected by damping, showing a non-monotonic variation with damping. The results suggest that careful tuning of the damping may be effectively employed to enhance power output for energy extraction applications or to suppress flow-induced vibration when it is detrimental to the structure. In the last part of the program, Floquet stability analysis was applied to the wake of a circular cylinder under viscoelastic support to determine how vibration affects the transition to wake threedimensionality. Across the range of reduced velocity considered, it was observed that the maximum Re value for which the flow remains two-dimensional is 212.