Influence of nonlinear turbulent friction on the system frequency response in transient pipe flow modelling and analysis

Duan, Huan‐Feng; Chuan, Tong; Lee, Pedro; Ghidaoui, Mohamed Salah

doi:10.1080/00221686.2017.1399936

Cited by 35 publications

(9 citation statements)

References 37 publications

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“…Thus, only the linearized steady friction is included in the following numerical applications. The nonlinear steady friction and unsteady friction (Meniconi et al 2014) can be also included using a method similar to the one presented in Duan et al (2018).…”

Section: Further Application and Results Analysismentioning

confidence: 99%

Transient Frequency Responses for Pressurized Water Pipelines Containing Blockages with Linearly Varying Diameters

et al. 2018

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Extended partial blockages in urban water supply systems (UWSS) are formed from complicated physical, chemical, and biological processes; thus, these blockages are commonly in random and nonuniform geometries. The transient-based blockage detection method (TBBDM) has been evidenced in many applications to be a promising way to diagnose these blockages. Despite the successful validation and application of the TBBDM in the literature, pipe blockages used in these studies were idealized and simplified to regular and uniform shape, which are however not common in practical UWSS, and thus invalidity and inaccuracy of this TBBDM has been widely observed in practical applications. This paper presents fundamental research on understanding the influence of more realistic and nonuniform blockages on transient wave behavior and the accuracy of current TBBDM. The blockage with a linearly varying diameter (termed as nonuniform blockage) is firstly investigated by the frequency domain analytical analysis for its impact on transient wave behavior, which is thereafter incorporated in the overall transfer matrix of transient frequency response for reservoir-pipeline-valve systems. The results indicate the nonuniform blockage may induce very different modification patterns on the frequency shift and amplitude change of transient waves from the uniform blockage situation.

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Section: Further Application and Results Analysismentioning

confidence: 99%

Transient Frequency Responses for Pressurized Water Pipelines Containing Blockages with Linearly Varying Diameters

et al. 2018

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“…The unsteady friction model is applied as well, and, further, decrease of the pressure fluctuation at a higher frequency results. It is noted that the nonlinearity of friction model is still a challenging factor for the frequency response of 1D water hammer when applied to practical problems since the high order terms will make non-negligible contributions at some specific conditions [38][39][40]. Duan et al [39] proposed a two-step analytical extension for the friction factor to consider the nonlinear turbulent friction term.…”

Section: Discussionmentioning

confidence: 99%

“…It is noted that the nonlinearity of friction model is still a challenging factor for the frequency response of 1D water hammer when applied to practical problems since the high order terms will make non-negligible contributions at some specific conditions [38][39][40]. Duan et al [39] proposed a two-step analytical extension for the friction factor to consider the nonlinear turbulent friction term. The numerical results showed that the contribution of the nonlinear steady friction term to the total frictional damping was highly dependent on the ratio of the generated transient intensity to the initial pipe discharge, which provided a factor to estimate the importance of the nonlinearity on the system frequency response analysis.…”

Section: Discussionmentioning

confidence: 99%

Model Analysis and System Parameters Investigation for Transient Wave in a Pump–Pipe–Valve System

Zu-bin

Pan

et al. 2020

Water

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The frequency responses of the transient wave propagating in a pump–pipe–valve system are studied with the system transfer matrix analysis (STMA) method. Being different to that in the reservoir–pipe–valve system, the transient wave is used as a long-distance communication technology in the pump–pipe–valve system, and very few works have been done on the model analysis and strategies to control the behavior of the oscillation signal of the pipe pressure. The theoretic solutions are studied with three internal friction models: frictionless, steady friction, and unsteady friction. The dimensionless parameter of the valve signal intensity (VSI) is proposed, and it is found to be a key factor affecting the quality of the wave propagation in the pipe. A larger pressure oscillation at the upstream side results when the VSI is smaller than one, whereas a more uniform amplitude for the resonances and anti-resonances is obtained when VSI approaches one. Some feasible suggestions are provided to obtain high quality wave signals.

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“…Capponi et al [38] evaluated the accuracy of frequency domain analysis and discovered linearization error, the mitigation of which requires a correction factor that enables frequency domain analysis to provide a nearly similar output as the method of characteristic (MoC). Duan et al [39] retained non-turbulent friction and provided an assessment of the pipe system under transient flow modeling in the frequency domain of a hydraulic system. As of late, many researches are concerned with crack detection, crack precise location, and the effects of crack and leakage in the pipeline system using the frequency domain as an essential practical approach.…”

Section: Introductionmentioning

confidence: 99%

Hydraulic Oscillation and Instability of A Hydraulic System with Two Different Pump-Turbines in Turbine Operation

Palikhe

Zhou

Bhattarai

2019

Water

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Hydraulic oscillation mainly reveals the undesirable pressure fluctuations which can cause catastrophic failure of any hydraulic system. The behavior of a hydraulic system equipped with two different pump-turbines was investigated through hydraulic oscillation analysis to demonstrate severe consequences induced in turbine operation, including S-shaped characteristics. The impedance of a pump-turbine has an essential role in the determination of the instability of the hydraulic system. The conventional way to determine the instability solely using the slope of a characteristic curve was improved, including the effect of guide vane opening in pump-turbine impedance, which consequently modified the instability expression. With this pump-turbine impedance, hydraulic oscillation analysis, including free oscillation analysis and frequency response analysis, was carried out. The free oscillation analysis entails the computation of complex natural frequencies and corresponding mode shapes of the system. These computations provided necessary information about the vulnerable position of vital hydraulic components and the scenario for self-excited oscillation. Further, the analysis illustrates the significant role of guide vane opening to prevent the system from becoming unstable. Lastly, frequency response analysis was performed for the system with an oscillating guide vane to obtain the frequency response spectrum, which revealed that the resonating frequencies are consistent with natural frequencies, and it supported free oscillation results.

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Influence of nonlinear turbulent friction on the system frequency response in transient pipe flow modelling and analysis

Cited by 35 publications

References 37 publications

Transient Frequency Responses for Pressurized Water Pipelines Containing Blockages with Linearly Varying Diameters

Transient Frequency Responses for Pressurized Water Pipelines Containing Blockages with Linearly Varying Diameters

Model Analysis and System Parameters Investigation for Transient Wave in a Pump–Pipe–Valve System

Hydraulic Oscillation and Instability of A Hydraulic System with Two Different Pump-Turbines in Turbine Operation

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