A Numerical Model for Hydraulic Transients in Drainage Systems

Politano, Marcela; Odgaard, Jacob; Jain, Subhash C.; Klecan, W.

doi:10.1061/40737(2004)394

Cited by 5 publications

(4 citation statements)

References 7 publications

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“…This model, also called a shock-fitting model is appropriate when the energy contained in the flow is sufficient to pressurize the flow through a hydraulic jump. The water depths and velocities near the interface are obtained using two shock-boundary conditions plus three characteristic equations (Politano et al, 2005).…”

Section: Interface Tracking Methods Of Analyzing Mixed Flowmentioning

confidence: 99%

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Modeling flow regime transition in intermittent water supply networks using the interface tracking method

Nyende‐Byakika¹

2012

Int. J. Phys. Sci.

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For several ailing water distribution networks in the world, during conditions of excessive withdrawals or insufficient water production, pressures fall to very low or even negligible values and consequently, no water can be supplied. Usually, most pipes have water which either fills or nearly fills their cross sectional areas but the pressure to push it out is absent. With conditions changing from pressurized to no pressure (free surface flow), existing water supply models are unable to simulate either free surface flow or the transition between free surface to pressurized flow. In this study, transient "low pressureopen-channel flow" (LPOCF) conditions were analyzed. The interest of this research lies in the coexistence of free surface and pressurized flow regimes with the aim of understanding the pressurization process of pipes. This was represented by a flow regime transition from free surface to pressurized flow through a moving interface along the pipeline. Results revealed the merits of applying full dynamic wave equations in the solution of transient LPOCF conditions in water distribution networks.

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Section: Interface Tracking Methods Of Analyzing Mixed Flowmentioning

confidence: 99%

“…x and velocity w . In this region, the equations that should be applied are the conservation of mass and momentum quantities given in Equations 17 and 20, respectively (Fuamba, 2003;Politano et al, 2005;Gomez and Achiaga, 2008).…”

Section: Solution Of Moving Interfacementioning

confidence: 99%

Modeling flow regime transition in intermittent water supply networks using the interface tracking method

Nyende‐Byakika¹

2012

Int. J. Phys. Sci.

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“…The arrangements of the horizontal system of pipelines add particularities that must be considered in each design situation. (Politano et al, 2005, for example) Predicting oscillations in vertical pipes naturally leads to comparisons between "free oscillation" and "damped oscillation" conditions, being the "damped oscillation" cases imposed by installed devices. In this sense, numerical procedures applied to proper governing equations are of practical use, giving quick support to professionals dealing with this theme.…”

Section: Introductionmentioning

confidence: 99%

Oscillations of Water Levels in Vertical Semi-Immersed Tubes: Analytical Solutions and Experimental Verification

Schulz¹,

Zhu²

2017

JAFM

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Experimental results for water level oscillations in vertical tubes, together with a theoretical solution for the flow in such tubes considering local and distributed energy losses, are presented and compared. The experimental data were obtained in small scale experiments, allowing adequately controlling the oscillations. The governing equation for the oscillations was obtained by applying the conservation laws of mass, momentum and energy for fluids. It is a second order nonlinear differential equation which was reduced to a first order differential Bernoulli equation. The obtained solution is composed by two different equations, one for the upwards motion and the other for the downwards motion, which together reproduce the oscillatory damped behavior of such flows. Numerical solutions of the differential equation were also checked. The experimental data and the theoretical and numerical results showed a good agreement between measured and calculated values of velocity and surface level for the first periods of oscillation.

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“…Transient changes in the flow rate and pressure for the simultaneous occurrence of free-surface and pressurized flows in partially filled pipelines can be modeled at varying levels of complexity (e.g., Benjamin 1968;Nydal and Andreussi 1991;Wiggert 1991, 1997;Bozkus et al 2004;Politano et al 2005;Vasconcelos et al 2006;Vasconcelos and Wright 2007;Bourdarias and Gerbi 2007;Leon et al 2009Leon et al , 2010Kayhan and Bozkus 2011). In the case of pipe filling, several types of pressure oscillations may be present, depending on the pipe-end ventilation condition (Zhou et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Emptying of Large-Scale Pipeline by Pressurized Air

et al. 2012

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Emptying of an initially water-filled horizontal PVC pipeline driven by different upstream compressed air pressures and with different outflow restriction conditions, with motion of an air-water front through the pressurized pipeline, is investigated experimentally. Simple numerical modeling is used to interpret the results, especially the observed additional shortening of the moving full water column due to formation of a stratified water-air "tail." Measured discharges, water-level changes, and pressure variations along the pipeline during emptying are compared using control volume (CV) model results. The CV model solutions for a nonstratified case are shown to be delayed as compared with the actual measured changes of flow rate, pressure, and water level. But by considering water-column mass loss due to the water-air tail and residual motion, the calibrated CV model yields solutions that are qualitatively in good agreement with the experimental results. A key interpretation is that the long air-cavity celerity is close to its critical value at the instant of minimum flow acceleration. The influences of driving pressure, inertia, and friction predominate, with the observed water hammer caused by the initiating downstream valve opening insignificantly influencing the water-air front propagation.

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A Numerical Model for Hydraulic Transients in Drainage Systems

Cited by 5 publications

References 7 publications

Modeling flow regime transition in intermittent water supply networks using the interface tracking method

Modeling flow regime transition in intermittent water supply networks using the interface tracking method

Oscillations of Water Levels in Vertical Semi-Immersed Tubes: Analytical Solutions and Experimental Verification

Emptying of Large-Scale Pipeline by Pressurized Air

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