Energy Dissipation of Flow in the Vortex Structure: Experimental Investigation

Mahmoudi-Rad, Mohammad; Khanjani, M. J.

doi:10.1061/(asce)ps.1949-1204.0000398

Cited by 19 publications

(15 citation statements)

References 26 publications

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“…The elaborations described in this paper are based on different experimental data [8,15,17,22,25,26]. All of them were collected by performing experiments in physical devices of vortex drop shafts in compliance with the standard layout of Figure 1.…”

Section: Physical Device Layoutmentioning

confidence: 99%

“…The chamber is always equipped with one or more air venting pipes to de-aerate the flow. In addition, the physical device of [22] was characterized by the possibility to add a sump and a baffle in the chamber, with the aim to mitigate the flow impact onto the chamber bottom and to increase the energy head dissipation. In the end, an outlet tunnel (subscript u), with a circular or rectangular cross-section of diameter D u or width b u , respectively, exits the dissipation chamber.…”

Section: Physical Device Layoutmentioning

confidence: 99%

“…Past experimental studies [4,21] ascertained that the energy head dissipation of vortex drop shafts with L s /D s larger than 50.0 (L s and D s are the shaft length and diameter, respectively) is almost 90%. Zhao et al [20] and Mahmoudi-Rad and Khanjani [22] demonstrated that energy head dissipation of 90% can also be reached for shafts of relatively small length L s between 10.0•D s and 16.0•D s when a water cushion is formed below the shaft outlet. For even shorter shafts, flow dissipation decreased down to about 70% [7,23].…”

Section: Introductionmentioning

confidence: 99%

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Energy Head Dissipation and Flow Pressures in Vortex Drop Shafts

Crispino

Contestabile

Vicinanza

et al. 2021

Water

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Vortex drop shafts are special manholes designed to link sewer channels at different elevations. Significant energy head dissipation occurs across these structures, mainly due to vertical shaft wall friction and turbulence in the dissipation chamber at the toe of the shaft. In the present study two aspects, sometimes neglected in the standard hydraulic design, are considered, namely the energy head dissipation efficiency and the maximum pressure force in the dissipation chamber. Different physical model results derived from the pertinent literature are analyzed. It is demonstrated that the energy head dissipation efficiency is mostly related to the flow impact and turbulence occurring in the chamber. Similarly to the drop manholes, a relation derived from a simple theoretical model is proposed for the estimation of the energy head loss coefficient. The analysis of the pressures measured on the chamber bottom allows to provide a useful equation to estimate the pressure peak in the chamber as a function of the approach flow energy head.

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Section: Physical Device Layoutmentioning

confidence: 99%

Section: Physical Device Layoutmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Energy Head Dissipation and Flow Pressures in Vortex Drop Shafts

Crispino

Contestabile

Vicinanza

et al. 2021

Water

View full text Add to dashboard Cite

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“…Other studies focused on energy loss found that depth of energy dissipation well has little effect on total energy dissipation rate and that the energy dissipation rate of the rotational flow is much smaller than that of the annular hydraulic jump in dissipation well [26,27]. Generally, the total energy dissipation ratio can exceed 70% under a reasonable design [26,28,29]. In other studies, the characteristics of velocity and pressure on a level swirling flow discharge tunnel were theoretically analyzed based on the combined vortex rule [30][31][32][33].…”

Section: Introductionmentioning

confidence: 99%

“…Overall, it can be said that previous advance made on the different parts and research aspects of the VDS was considerable. However, unlike the previous VDS with a tangential slot inlet [9,15,29], widely applied in an urban drainage system, the hydraulic behavior of a VDS spillway equipped with an elliptical tangential inlet has not been detailed addressed. Such shape originated in China, and it is generally considered superior with better discharge capacity and flow pattern than the former [1].…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Flow of a Vortex Drop Shaft Spillway with an Elliptical Tangential Inlet

Zhou

Yin

et al. 2021

Water

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Vortex drop shaft (VDS) spillways are eco-friendly hydraulic structures used for safely releasing flood. However, due to the complexity of the three-dimensional rotational flow and the lack of suitable measuring devices, current experimental work cannot interpret the flow behavior reliably inside the VDS spillway, consequently experimental and CFD study on a VDS spillway with an elliptical tangential inlet was conducted to further discern the interior three-dimensional flow behavior. Hydraulic characteristics such as wall pressure, swirl angle, annular hydraulic height and Froude number of the tapering section are experimentally obtained and acceptably agreed with the numerical prediction. Results indicated that the relative dimensionless maximum height of the standing wave falls off nearly linearly with the increasing Froude number. Nonlinear regression was established to give an estimation of the minimum air-core rate. The normalized height of the hydraulic jump depends on the flow phenomena of pressure slope. Simulated results sufficiently reveal the three-dimensional velocity field (resultant velocity, axial velocity, tangential velocity and radial velocity) with obvious regional and cross-sectional variations inside the vortex drop shaft. It is found that cross-sectional tangential velocity varies, resembling the near-cavity forced vortex and near-wall free vortex behavior. Analytic calculations for the cross-sectional pressure were developed and correlated well with simulated results.

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