Coupled-Mode Vibration of Gates with Simultaneous Over- and Underflow

Ishii, Noriaki; Knisely, Charles W.; Nakata, Akinori

doi:10.1006/jfls.1994.1022

Cited by 12 publications

(5 citation statements)

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“…They believed that turbulent pressure and multi-vortex mixing were the main reasons for the gate flow-induced vibration. Moreover, some researchers pointed out that vortex shedding behind the gate bottom is the cause of the gate vibration [6,7]. Those results, nevertheless, were mostly obtained for low-speed flow conditions or in fixed gate openings.…”

Section: Flow Field Distributionmentioning

confidence: 99%

“…Thang [5,6] posited that gate vibration was caused by downstream vortex resonance and pointed out that the slope of lift coefficient curve was taken as a criterion by which to judge the gate dynamic stability. Ishii and Knisely [7] reckoned that the fluid feedback force induced by gate vibration mainly included two aspects: pressure pulsation caused by flow and alternating excitation derived from the vortex at the gate bottom. Kunihiro et al [8] expounded that the curved gate vibration belonged to the self-excited vibration in the small gate opening.…”

Section: Introductionmentioning

confidence: 99%

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Holding Force and Vertical Vibration of Emergency Gate in the Closing Process: Physical and Numerical Modelling

Wang

Liu

2021

Applied Sciences

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A two-dimensional unsteady fluid–structure interaction numerical model was established, based on the physical model test, to investigate the influence of vertical vibration on the holding force of an emergency gate in the closing process. Gate motion was controlled by the user-defined function in Fluent. Attention was paid to the relationship between the vertical vibration, hydrodynamic loads and flow discharge. The experiment results show that holding force has three typical forms in the closing process and it is related to the service gate height. The numerical model can reflect the gate vertical vibration and the gate-closing displacement in the form of steps. Gate vertical vibration in the closing process is a motion-induced vibration caused by gate active falling. Moreover, the transition from full-flow to open-flow behind the emergency gate has a great influence on the gate vertical vibration. With a small gate opening, gate vertical vibration makes the flow discharge fluctuation increase. Furthermore, flow discharge has an influence on the gate body loads, which is mainly concentrated in the upstream plate and gate bottom. Finally, the lift force coefficient at the gate bottom is different from the standard and is mainly controlled by the outflow boundary condition. The simulation result is in good agreement with the experiment and the relative error meets engineering requirements, suggesting that the numerical model can successfully simulate the gate fluid–structure interaction and reproduce the characteristics of physical quantities in the closing process.

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Section: Flow Field Distributionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Holding Force and Vertical Vibration of Emergency Gate in the Closing Process: Physical and Numerical Modelling

Wang

Liu

2021

Applied Sciences

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“…Generally, the dominant frequency of flow-induced pressure fluctuation ranges from 0 to 2 Hz and the high frequency vibration is unlikely to be caused. However, the fluctuating pressure generated by the high-velocity discharge flow may consist of high-frequency components [35], and the high-frequency vibration of the hydraulic gate occurs frequently in engineering practice [6,36]. The detailed mechanism for the flow-induced vibration of hydraulic gates needs further investigation.…”

Section: Vibration Of the Mid-level Outlet Radial Gatementioning

confidence: 99%

Analysis of the Cause and Mechanism of Hydraulic Gate Vibration during Flood Discharging from the Perspective of Structural Dynamics

Lian

Lin

et al. 2020

Applied Sciences

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According to the results of a dynamic prototype test for the surface outlet radial gate on the Jinping high arch dam during the flood discharging process, a novel cause of vibration fundamentally different from the traditional causes of flow-induced radial gate vibration, is analyzed for the first time. Under the condition that the flood is discharged only from mid-level outlets, an accompanying vibration of the surface outlet gate is induced by the vibration of the closely spaced mid-level outlet gates. It is counterintuitive that the most intense vibration occurs when the surface outlet gate is closed and, on the contrary, the vibration is reduced when the gate is opened and subjected to flow excitation. In order to analyze and explain this accompanying vibration phenomenon, a theoretical model is developed based on the conventional theory of passive vibration absorbers. The difference between the proposed and conventional theoretical models is that more complex load and damping conditions are considered, and more attention was paid to the dynamic behavior of the accessory structure. Then, the cause and mechanism for the surface outlet gate vibration is clarified in detail, based on the proposed theoretical model. The comprehensive analysis and mutual verification of the prototype test, theoretical derivation and numerical simulation, indicate that the clarification and the proposed theoretical model is reasonable and accurate. The research reported in this paper will be beneficial for the design, operation and maintenance of the hydraulic gates installed on high arch dams.

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“…While Thang and Naudascher (1986) proposed that galloping is the main reason for self-excitation on gates with underflow, Kanne et al (1991) showed that both effects can play a significant role in the self-excitation process. Ishii and Knisely (1992), Ishii et al (1994) and Ishii et al (2014) developed additional models for press-shut mechanisms involving the coupling of multiple degrees of freedom (Figure 1 f), calling it the "coupled mode press-shut" effect. An extensive summary of research, construction recommendations and applicable solutions can be found in Naudascher and Rockwell (1994), Kolkman and Jongeling (2007) and Ishii et al (2018).…”

Section: Review Of the Press-shut Mechanismmentioning

confidence: 99%

“…developed a stability indicator to check vibration tendencies for a bath-plug type valve (Figure1 h) and transferred the results to different kinds of gates. WhileThang and Naudascher (1986) proposed that galloping is the main reason for self-excitation on gates with underflow,Kanne et al (1991) showed that both effects can play a significant role in the self-excitation process Ishii and Knisely (1992),Ishii et al (1994). andIshii et al (2014) developed additional models for press-shut mechanisms involving the coupling of multiple degrees of freedom (Figure1f), calling it the "coupled mode press-shut" effect.…”

mentioning

confidence: 99%

Numerical Simulation of Flow-Induced Vibration on Gates With Underflow

Göbel¹,

Gebhardt²,

Deutscher³

et al. 2019

38th IAHR World Congress - "Water: Connecting the World"

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Flow-induced vibrations are an important issue in the design and operation of weir gates. Various mechanisms of vibration excitation are known. For underflow weir gates, the so-called press-shut mechanism is known to be a possible source of excitation. Hereby, the movement of the gate affects the flow regime in a way that a force is produced that acts in the direction of the gates movement. This self-excited process can lead to severe gate vibrations. Due to the coupled nature of self-excitation, it is insufficient to compare the distinct flow-induced forces and the natural frequency of the gate in a static model. A coupled approach is required in which both the flow and the gate movement are represented in a fully transient manner.Self-excited vibrations at hydraulic gates with underflow are often based on the coupling between vibration of the gate and the attributed flow-rate fluctuation. This phenomenon is referred as the press-shut mechanism. The investigation of self-excited vibrations requires the use of coupled models that reflect the transient flowregime and the motion of the body. A practical approach is developed which employs coupled numerical simulation to model the interaction between the vibrating gate and surrounding flow field. The energy that is transferred from the flow to the vibration is estimated as a value for vibration tendency. The method is applied to two practical examples of gates with underflow and verified with field measurements.

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Coupled-Mode Vibration of Gates with Simultaneous Over- and Underflow

Cited by 12 publications

References 0 publications

Holding Force and Vertical Vibration of Emergency Gate in the Closing Process: Physical and Numerical Modelling

Holding Force and Vertical Vibration of Emergency Gate in the Closing Process: Physical and Numerical Modelling

Analysis of the Cause and Mechanism of Hydraulic Gate Vibration during Flood Discharging from the Perspective of Structural Dynamics

Numerical Simulation of Flow-Induced Vibration on Gates With Underflow

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