2021/05/25 by Shayan Heydari, S. Heydari, Heydari, S. +9
Engineering · Environmental Science · Physics and Astronomy · #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Fluid Dynamics and Turbulent Flows #Fluid Dynamics and Vibration Analysis #Wind and Air Flow Studies #physics.flu-dyn
paper · pdf · doi:10.48550/arxiv.2105.11663
arxiv created 2021/05/25 · openalex publication_date 2021/05/25 · arxiv updated 2021/05/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present a numerical study to investigate the fluid-structure interaction of a flexible circular cantilever cylinder in a uniform cross-flow. We employ a fully-coupled fluid-structure solver based on the three-dimensional Navier-Stokes equations and the Euler-Bernoulli beam theory. We examine the dynamics of the cylinder for a wide range of reduced velocities (U^*), mass ratios (m^*), and Reynolds numbers (Re). Of particular interest is to explore the possibility of flow-induced vibrations in a slender cantilever cylinder of aspect ratio AR=100 at laminar subcritical Re regime (i.e., no periodic vortex shedding). We assess the extent to which such a flexible cylindrical beam can sustain flow-induced vibrations and characterize the contribution of the beam's flexibility to the stability of the wake at low Re. We show that when certain conditions are satisfied, the flexible cantilever cylinder undergoes sustained large-amplitude vibrations. The frequency of the oscillations is found to match the frequency of the periodic fluid forces for a particular range of system parameters. In this range, the frequency of the transverse vibrations is shown to match the first-mode natural frequency of the cylinder, indicating the existence of the lock-in phenomenon. The range of the lock-in regime is shown to have a strong dependence on Re and m^*. We discover that unlike the steady wake behind a stationary rigid cylinder, the wake of a low mass ratio flexible cantilever cylinder could lose its stability in the lock-in regime at Reynolds numbers as low as Re=22. A combined VIV-galloping type instability is shown to be the possible cause of the wake instability at this Re regime. These findings attempt to generalize our understanding of the flow-induced vibrations in flexible cantilever structures and can have a profound impact on the development of novel flow-measurement sensors.