Abstract: The Karman vortex shedding resonance at the trailing-edge of stay vanes in some units of right bank of Three Gorges Hydropower station is investigated. According to the actual operation of units and the characteristics of abnormal noise, the Karman vortex shedding resonance at the trailing-edge of stay vanes is simulated by using computational fluid dynamics, CFD numerical technology. Based on the CFD numerical model established, quantitative analysis on the vibration performance of Karman vortex shedding is achieved by using the software FLUENT. Then, dynamic behavior analysis of stay vanes underwater is implemented by using fluid-structure interaction method, and natural frequency of structure underwater is obtained. It is shown that the frequency of Karman vortex shedding is very close to the natural frequency of structure underwater. This phenomenon could cause interaction between them and local vibration easily. By validation with the vibration and noise test on site, vibrating source causing abnormal noise and main reasons inducing the Karman vortex shedding resonance are found. Finally, by comparative analysis of different sectional profiles of trailing-edge of stay vanes, the optimization scheme for preventing and erasing the Karman vortex shedding resonance is raised.

Key words: Abnormal noise, Karman vortex shedding resonance, Numerical model, Stay vane, Trailing-edge profile