Abstract
During the flood discharge in large-scale hydraulic engineering projects, intense flow-induced vibrations may occur in hydraulic gates, gate piers, spillway guide walls, etc. Furthermore, the vibration mechanism is complicated. For the spillway guide wall, existing studies on the vibration mechanism usually focus on the vibrations caused by flow excitations, without considering the influence of dam vibration. According to prototype tests, the vibrations of the spillway guide wall and the dam show synchronization. Thus, this paper presents a new vibration mechanism of associated-forced coupled vibration (AFCV) for the spillway guide wall to investigate the dynamic responses and reveal coupled vibrational properties and vibrational correlations. Different from conventional flow-induced vibration theory, this paper considers the spillway guide wall as a lightweight accessory structure connected to a large-scale primary structure. A corresponding simplified theoretical model for the AFCV system is established, with theoretical derivations given. Then, several vibrational signals measured in different structures in prototype tests are handled by the cross-wavelet transform (XWS) to reveal the vibrational correlation between the spillway guide wall and the dam. Afterwards, mutual analyses of numeral simulation, theoretical derivation, and prototype data are employed to clarify the vibration mechanism of a spillway guide wall. The proposed mechanism can give more reasonable and accurate results regarding the dynamic response and amplitude coefficient of the guide wall. Moreover, by changing the parameters in the theoretical model through practical measures, the proposed vibration mechanism can provide benefits to vibration control and structural design.
Highlights
In recent years, comprehensive hydraulic engineering projects with high dams and large reservoirs have been rapidly developing, especially in China, such as Three Gorges, Jinping, and Xiluodu.Simultaneously, flow-induced vibrations (FIV) of hydraulic structures, which frequently occur in these projects, have posed a significant threat to engineering safety [1]
Flow-induced vibrations (FIV) of hydraulic structures, which frequently occur in these projects, have posed a significant threat to engineering safety [1]
To investigate the mechanism of guide wall vibration, the amplitude coefficient of the accessory structure is calculated to analyze its dynamic response in the associated-forced coupled vibration (AFCV) system, and the aforementioned two kinds of vibrations are taken into account and a comparison is made to explore their contribution to the coupled vibration
Summary
Comprehensive hydraulic engineering projects with high dams and large reservoirs have been rapidly developing, especially in China, such as Three Gorges, Jinping, and Xiluodu. Flow-induced vibrations (FIV) of hydraulic structures, which frequently occur in these projects, have posed a significant threat to engineering safety [1]. The above studies are focused on structural optimizations and excitations; for the vibration mechanism and dynamic response of the guide wall, conventional research methods are inadequate. Conventional vibration analyses usually employ the Fourier Transform (FT) to obtain the vibrational characteristics [21] Another common signal processing method is Empirical Mode Decomposition (EMD), and its various modifications. InInconclusion, the studies on the FIV of spillway guide walls are inadequate, as the conventional methods usually focus on the vibrations caused by flow excitations, but the influence of dam methods usually focus on the vibrations caused by flow excitations, but the influence of dam vibration vibration is always ignored, leading to the inaccuracy and irrationality of vibration analyses. All of the measuring points were tested simultaneously under the same working condition
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