Vortex-induced vibration of a wavy elliptic cylinder
| Autor: | Peter W. Bearman, Gustavo R. S. Assi |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Flow visualization
Technology FLOW Fluids & Plasmas 020101 civil engineering 02 engineering and technology Wake Flow-induced vibration Mechanics 01 natural sciences CIRCULAR-CYLINDERS 09 Engineering 010305 fluids & plasmas 0201 civil engineering DRAG Physics::Fluid Dynamics symbols.namesake Engineering Drag reduction 0103 physical sciences Cylinder PASSIVE CONTROL FLUCTUATING FORCES LOW-MASS VORTICES Physics Suppression Science & Technology Mechanical Engineering WAKE-INDUCED VIBRATION Reynolds number Vorticity BLUFF-BODY Vortex Engineering Mechanical VIBRAÇÕES Vortex-induced vibration Drag symbols Seal whiskers |
| Zdroj: | Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP |
| Popis: | This paper shows that three-dimensional separation lines on a wavy cylinder may be correlated by the lateral movement of the body responding to flow-induced excitations. Vortex-induced vibration (VIV) of a wavy elliptic cylinder is investigated by mean of experiments in a water channel in the range of Reynold number between 1,500 to 15,000. Results are compared with those for a plain circular cylinder of equivalent diameter with a combined mass–damping parameter of 0.018. Curves of displacement and frequency of vibration showed that the hydroelastic mechanism that drives the wavy cylinder into VIV is not different from that of a plain cylinder. Detailed decomposition of the fluid forces supports this conclusion. The reason for such similar behaviour is the correlation of the sinuous separation lines as the wavy cylinder starts to oscillate. Flow visualization reveals that the three-dimensional surface of the wavy cylinder affects the formation of vortices in the near wake, generating streamwise and cross-flow vorticity associated with the wavelength of the surface. However, once the cylinder is free to respond to VIV, moving in the cross-flow direction, coherent vortex filaments once more dominate the near wake. |
| Databáze: | OpenAIRE |
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