FSI simulations of fluid-elastic instabilities of a clamped-clamped cylinder in axial flow

A cylinder clamped at both ends and subjected to an axial flow will typically become unstable with increasing axial flow velocity. At low velocity the cylinder will buckle and, as the flow velocity is further increased, flutter will occur. These instabilities can be devastating in some applications such as nuclear reactor cores or can be put to good use in energy harvesting tools. A substantial amount of analytical and experimental work has already been performed on the stability of clamped-clamped cylinders in axial flow. Consequently, the dynamic behavior is well-documented and experimental data is readily available. Numerical simulations on the topic are rather scarce but could give access to information that is hard to obtain experimentally or capture in a theoretical model. However, simulating the dynamic behavior requires a two-way coupling, which entails a certain computational cost. Furthermore, the rather large displacements associated to the instabilities can cause problems due to mesh distortion in the flow solver, especially in confined geometries. In this research fluid-structure interaction simulations are performed on a clamped-clamped cylinder subjected to axial flow for a range of inlet velocities. The critical velocities for buckle and flutter and their amplitudes are compared to experimental data obtained from literature. In the flow solver a Chimera technique is used which allows for large structural deformations without degrading the mesh. By doing so the concept could also be extended to cantilevered cylinders which show even larger displacements. One of the goals of the research is to investigate the effect of compressibility on the stability.

ISBN:9791069996823

Publication year:2022

Accessibility:Closed