Boundary-Shear Stress in Unsteady Turbulent Pipe Flow

Carstens, M. R.; Roller, John Edwin

doi:10.1061/jyceaj.0000276

Cited by 47 publications

(6 citation statements)

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“…This approach yields satisfactory outcomes with less numerical accuracy as the convolution integral is approximated by a small number of weighted coefficients [30,31]. Carstens et al [32] introduced instantaneous acceleration-based methods based on the assumptions that unsteady friction damping results from transient local and convective accelerations. Several alternative formulations [33][34][35] have been proposed since then.…”

Section: Water Hammer Equation With Unsteady Frictionmentioning

confidence: 99%

Insights into CFD Modelling of Water Hammer

Kumar,

Pu,

Hanmaiahgari

et al. 2023

Water

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A problem with 1-D water hammer modelling is in the application of accurate unsteady friction. Moreover, investigating the time response of fluid dynamics and unsteady turbulence structures during the water hammer is not possible with a 1-D model. This review article provides a summary of 1-D modelling using the recent finite volume approach and the discussion extends to a quasi-2-D model and historical developments as well as recent advancements in 3-D CFD simulations of water hammer. The eddy viscosity model is excellent in capturing pressure profiles but it is computationally intensive and requires more computational time. This article reviews 3-D CFD simulations with sliding mesh, an immersed solid approach, and dynamic mesh approaches for modelling valve closures. Despite prediction accuracy, a huge computational time and high computer resources are required to execute 3-D flow simulations with advanced valve modelling techniques. Experimental validation shows that a 3-D CFD simulation with a flow rate reduction curve as a boundary condition predicted accurate pressure variation results. Finally, a brief overview of the transient flow turbulence structures for a rapidly accelerated and decelerated pipe flow using DNS (Direct numerical simulation) data sets is presented. Overall, this paper summarises past developments and future scope in the field of water hammer modelling using CFD.

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Section: Water Hammer Equation With Unsteady Frictionmentioning

confidence: 99%

Insights into CFD Modelling of Water Hammer

Kumar,

Pu,

Hanmaiahgari

et al. 2023

Water

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“…(1) Métodos com base empírica ou baseados em acelerações instantâneas, como é o caso dos métodos apresentados por Daily et al (1956), Carstens e Roller (1959), Sawafat e Polder (1973) e Brunone et al (1991); (2) Métodos com base física, dentre os quais destacam-se os métodos propostos por Zielke (1968) e Vardy e Brown (1993, 2003, 2004. Dessa revisão foram identificados o modelo de Brunone et al (1991), de base empírica e o modelo de Vardy et al (1993), com base física, com o propósito de serem comparados em etapa posterior da pesquisa.…”

Section: Metodologiaunclassified

“…De fato, não exigem muita memória para o armazenamento de variáveis de escoamento previamente calculadas e, em geral, não dependem de procedimentos iterativos complexos (Pothof, 2008). Existe uma variedade de modelos unidimensionais para o atrito variável, que podem ser classificados, conforme Pothof (2008), em duas classes: (1) Métodos com base empírica ou baseados em acelerações instantâneas, como é o caso dos métodos apresentados por Daily et al (1956), Carstens e Roller (1959), Sawafat e Polder (1973) e Brunone et al (1991); (2) Métodos com base física, dentre os quais destacam-se os métodos propostos por Zielke (1968) e Vardy e Brown (1993, 2003, 2004. Dentre os métodos incluídos na classe (1) destaca-se o de Brunone et al (1991), que descreve com boa acurácia os escoamentos transientes turbulentos em sistemas simples.…”

Section: Introductionunclassified

Avaliação de modelos de atrito variável em transientes hidráulicos

Ferreira¹,

Barbosa²,

Castro³

2015

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“…Daily et al (1956) developed a model in which the unsteady friction is dependent on instantaneous mean flow velocity and instantaneous local acceleration. Carstens & Roller (1959) presented the influence of instantaneous mean flow velocity and instantaneous local acceleration on friction terms. The instantaneous-acceleration unsteady friction model is simple to implement and computationally efficient but is difficult to determine the empirical parameter.…”

Section: Introductionmentioning

confidence: 99%

3D CFD simulation and analysis of transient flow in a water pipeline

Cao

Zhou

et al. 2022

Journal of Water Supply: Research and Technology-Aqua

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A three-dimensional (3D) computational fluid dynamics (CFD) approach is developed to elaborate the water-hammer pipe flow and 3D detailed dynamic characteristics of a closing ball valve. The proposed CFD approach considers the water compressibility and the viscous sublayer, which are sometimes neglected in previous studies. Comparisons of the CFD results, the measured pressures and the one-dimensional results, demonstrate that the current 3D CFD approach better reproduces the experimental pressure oscillations while helping to visualize the associated physical processes and to further explore the 3D transient characteristics. The mean velocity distributions in the radial direction significantly change as the pipe transient progresses, which is closely associated with transient shear stress. Mean velocity variations at the valve during the closing process undergo three distinct stages: slight change, then drastic reduction, and finally slowing down. Head loss coefficient and discharge coefficient of the valve change as the valve closing time shortens.

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Boundary-Shear Stress in Unsteady Turbulent Pipe Flow

Cited by 47 publications

References 0 publications

Insights into CFD Modelling of Water Hammer

Insights into CFD Modelling of Water Hammer

Avaliação de modelos de atrito variável em transientes hidráulicos

3D CFD simulation and analysis of transient flow in a water pipeline

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