An improved model for the tangential velocity distribution in strong free-surface vortices: an experimental and theoretical study

Mulligan, Seán; Creedon, Leo; Casserly, John; Sherlock, Richard

doi:10.1080/00221686.2018.1499050

Cited by 18 publications

(10 citation statements)

References 23 publications

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“…Otherwise, the aspect ratio between the diameter of the tank and the diameter of the outlet hole determines the diameter of the air vortex formed in the tank (Wanchat et al, 2013). However, the results of this study are similar to the study conducted by Mulligan et al, (2019) where they compare experimental results with data by analytical models. In this study, the error amounts to up to 30% between models and experimental data.…”

Section: Discussionsupporting

confidence: 75%

“…By reviewing the literature, it was determined that the numerical results delivered by ANSYS were compared with the models proposed by Einstein & Li, (2011), Vatistas et al, (1986), Rosenhead, (1930), and Hite Jr & Mih, (1994 (Table 1). They were compared to each other and with the results of an experimental test in previous research (Mulligan et al, 2019). In addition, these models have a higher level of detail in their variables compared to unused studies.…”

Section: Numerical Vs Analytical Modelsmentioning

confidence: 99%

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Numerical Study and Theoretical Comparison of Outlet Hole Geometry for a Gravitational Vortex Turbine

Sánchez

Rio

Pujol

2021

Indonesian J. Sci. Technol

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The gravitational water vortex turbine is an alternative to renewable energies, it transforms the hydrokinetic energy of the rivers into electric energy and it does not require a reservoir. According to studies carried out, the hydraulic efficiency can increase or decrease according to the turbine geometrical configuration. This paper presents a numerical (CFD) and analytical comparison between conical and cylindrical designs for the outlet. The results show a higher performance for conical geometry than the cylindrical tank. The fluid behavior in CFD and analytical studies presents a tangential velocity increase near to air core and outlet hole (similar behavior). The maximum theoretical power generated was 167 W and 150 W for conical and cylindrical design respectively. The differences between geometries of the outlet holes using CFD and analytical models were 11 and 7%, respectively. However, the closest results to the CFD model had different values of 31 and 29% for conical and cylindrical design, respectively. The furthest result regarding the CFD study was 55%. The principal difference is due to tank geometry, the change in discharge zone, as well as the ratio of diameter tank and outlet hole can increase or decrease the tangential velocity and make a stronger and more stable vortex formation. The theoretical power generated is a good parameter to select the height to place the rotor.

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Section: Discussionsupporting

confidence: 75%

Section: Numerical Vs Analytical Modelsmentioning

confidence: 99%

Numerical Study and Theoretical Comparison of Outlet Hole Geometry for a Gravitational Vortex Turbine

Sánchez

Rio

Pujol

2021

Indonesian J. Sci. Technol

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“…Timilsina et al [5] provided a comprehensive overview of various theoretical, analytical, and empirical models that characterize and measure the vortex flow field, pressure, and tangential velocity and the interaction between vortex and turbine. Mulligan et al [116] indicated that a water vortex can be explained by the theory of conservation of angular momentum. Fluid particles moving radially and with a small inflow of tangential velocity generate a significant vortex structure close to the centre of the discharge.…”

Section: Vortex Dynamicsmentioning

confidence: 99%

A Review of Gravitational Water Vortex Hydro Turbine Systems for Hydropower Generation

2023

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Hydropower is one of the most sustainable and desirable renewable energy sources. Gravitational water vortex hydro turbine (GWVHT) systems are one of the most suitable and sustainable renewable power generation devices for remote and rural areas, particularly in developing countries, owing to their small scales and low costs. There are various GWVHT systems with different configurations and various operating conditions. The main components of a GWVHT system include the inlet and outlet channels, a basin, and a turbine on which there are a number of blades attached. This paper presents a comprehensive review regarding the progress and development of various GWVHT systems, covering broad aspects of GWVHT systems, particularly various types of basins, inlet and outlet channels, turbines with blades which have different shapes, orientations, sizes, numbers, etc. The nature of the previous studies is summarised. The fundamentals of the vortex dynamics involved and the quantitative analysis of the performance of GWVHT systems are also described. The turbulence models and multiphase models used in some leading numerical simulation studies have been reviewed. As a case study, the implementation of a GWVHT system in PNG is presented. Based on the review of previous studies regarding GWVHT systems, the major issues and challenges are summarised, and some key topics are recommended for future research work on the performance of GWVHT systems.

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“…However, numerous authors found significant discrepancies in this model near the vortex core region. Mulligan et al, (2018) studied the tangential velocity distribution extensively using particle tracking velocimetry and reported that this discrepancy was likely due to neglecting the axial flow effects in this region. To improve on this, Mulligan et al (2018) presented a corrected equation as follows:…”

Section: Vortex Chamber Velocity Distributionsmentioning

confidence: 99%

“…More recently, undertook a study on twelve variations of the scroll chamber to develop a simple empirical model for determining the depth discharge based only on the approach flow geometry. Subsequently, Mulligan et al (2018) investigated the tangential velocity profiles across the scroll chamber using laser particle tracking velocimetry.…”

Section: Subcritical Intake Flowsmentioning

confidence: 99%

Vortex Drop Shaft Structures: State-of-the-Art and Future Trends

Mulligan¹,

Plant²,

Clifford³

2019

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

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Vortex drop shaft structures have played a critical role in hydraulic engineering; from one of their first applications in hydroelectric energy dissipation in the 1940s, to numerous contemporary installations throughout modern day urban drainage infrastructure. They are known to convey flows up to 1400 m 3 /s through drop heights of 190 m and due to their small footprint, stable flow mechanics and enhanced energy dissipation, they are often considered to be the most successful form of hydraulic drop structure. There are several design questions on various aspects of vortex drop shaft structures that have not yet been addressed in the laboratory environment or at full-scale and moreover will require full appreciation by engineering practitioners in future years. This article summarizes over 75 years of research and development of vortex drop shafts including types of structure, applications, laboratory modelling techniques, physical modelling studies and recent advancements in multiphase numerical modelling. The article discusses the hydraulics of various types of vortex drop shaft structures such as the key design differences between subcritical and supercritical intakes, energy dissipation, and aeration and presents the insights gained from successful case study commercial projects. The outcomes of seminal research studies and projects are discussed in detail and areas that are deemed to require further research and development are highlighted.

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An improved model for the tangential velocity distribution in strong free-surface vortices: an experimental and theoretical study

Cited by 18 publications

References 23 publications

Numerical Study and Theoretical Comparison of Outlet Hole Geometry for a Gravitational Vortex Turbine

Numerical Study and Theoretical Comparison of Outlet Hole Geometry for a Gravitational Vortex Turbine

A Review of Gravitational Water Vortex Hydro Turbine Systems for Hydropower Generation

Vortex Drop Shaft Structures: State-of-the-Art and Future Trends

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