Numerical Simulations of Flow-Induced Vibrations past a Deformable Cylinder

When a viscous fluid flows past a blunt body at sufficiently large Reynolds numbers (Re), it naturally develops an oscillatory motion that manifests itself in the time-periodic variation of the wake behind the body, a von Karman vortex street (VKVS). If the body is elastic, the frequency of the oscillations may be close to the natural frequency of the body, thus producing a resonance phenomenon that can lead to catastrophic consequences. A remarkable example is the collapse of the Tacoma Narrows Bridges. Traditionally, most numerical simulations and experiments are flow past a rigid body. In this thesis, the ANSYS Workbench coupling system was used to investigate this question in the care of an elastic body (FSI) in the shape of a cylinder clamped at both ends. We modeled the cylinder as silicon rubber to allow sufficiently large deformation even at small Renolds numbers. This simulation starts from a relatively low Reynolds number (Re100) up to a medium-range of values (Re2000). Results are compared with flow past a rigid cylinder, and it turns out that quite different phenomena are observed. The deformable cylinder prevents or mitigates vortex shedding to some degree. Besides, bifurcation patterns are varying from those observed in rigid ones. Drag and lift coefficients and displacements plots specifically demonstrate the occurrence of the phenomena. Deep understandings of such phenomena may improve configurations of architectures to avoid flow-induced vibrations and vortex-induced vibrations (VIVs)