Abstract Summary
Many civil, transport and other engineering structures (chimneys, submarine pipelines, risers, etc) suffer from appearance of vibrations in these systems. It often occurs when the whole structure of its part is an elastic, or elastically mounted rigid bluff body immersed in a fluid flow. The vortices shedding from the body leads to vortex-induced vibrations (VIV). When a structural natural frequency is close to the shedding frequency the bluff body experiences a periodic and oscillates. VIV can lead to fatigue damage accumulation up to the destruction of the structure, but they can also be used to harvest electric energy from the kinetic energy of air or water flow. In this study, vortex-induced vibrations of an elastic cylinder near a finite-length plate are experimentally investigated in aerodynamic tunnel. Rubber cylinder of diameter D = 6 mm was spanned in the test section of a wind tunnel near the plate of length nearly 6D. The oscillation amplitude peak for a single cylinder was 0.3D, the Reynolds number of the peak-amplitude regime based on cylinder diameter was in the range 180...260. For a cylinder located sufficiently upstream from to the plate trailing edge it was found that the oscillation amplitude ratio A/D decreases if the gap ratio G/D between the cylinder surface and the plate reduces. However, for the cylinder location at the same level or downstream from the plate trailing edge, there are regions of essentially larger oscillation amplitudes compared to the isolated cylinder case. The maximum amplitude increase by 39% was obtained. Smoke visualizations revealed complex interference of the plate cylinder wakes were conducted. When the gap ratio decreases, the shift of the lock-in range to higher velocities was observed. The modification of the shedding laws in the proximity of the plate is studied.
