Landscapes of Water, History, Innovation and Sustainable Design (original) (raw)

Current knowledge in hydraulic jumps and related phenomena. A survey of experimental results

European Journal of Mechanics - B/Fluids, 2009

THREE-DIMENSIONAL FEATURES OF UNDULAR HYDRAULIC JUMPS

26th IAHR Biennal Congress, London, UK, 1995

In open channels, an undular hydraulic jump 1s a stationary transition from super- to sub-critical flow. It is characterised by the development of regular and irregular free-surface undulations downstream of the jump. The three-dimensional characteristics of undular hydraulic jumps with fully-developed upstream flows have been investigated experimentally. The results confirm the importance of the lateral shock waves and their effects on the flow field.

Hydraulic Jumps: Bubbles and Bores

16th Australasian Fluid Mechanics Conference (AFMC), 2007

The hydraulic jump is the sudden transition from a high-velocity open channel flow regime to a subcritical flow motion. The flow properties may be solved using continuity and momentum considerations. In this plenary lecture, recent advances in turbulent hydraulic jumps are reviewed: the non-breaking undular hydraulic jump, the positive surge and tidal bore, and the air bubble entrainment in hydraulic jumps with roller. This keynote lecture demonstrates that the hydraulic jump is a fascinating turbulent flow motion that remains poorly understood. Undular Hydraulic Jumps Undular hydraulic jumps are characterised by a smooth rise of the free-surface followed by a train a well-formed stationary waves (Fig. 1A, 2B & 3). They are sometimes experienced in natural waterways and rivers at a break in bed slopes. (A related situation is the "Morning Glory" cloud pattern observed in Northern Australia, sometimes called an undular jump (Clarke 1972, Clarke et al. 1981).) Most hydraulic and fluid mechanics textbooks ignore the undular hydraulic jump in their section on open channel flows. A few studies of hydraulic jumps included some undular jump cases : e.g., Darcy and Bazin (1865), Bakhmeteff and Matzke (1936), Binnie and Orkney (1955) (Fig. 2). Fawer (1937) detailed clearly the main features of undular hydraulic jumps but his contribution was ignored for decades. Modern studies of undular jumps included Montes (1986), Ryabenko (1990), Chanson and Montes (1995), Montes and Chanson (1998), Ohtsu et al. (2001). These works showed that undular jumps may occur for upstream Froude numbers ranging from unity up to 3 to 4. Recent experiments (Table 1) are re-analysed herein and the results provide some new understanding of the complicated flow patterns in undular hydraulic jumps.

Characteristics of Undular Hydraulic Jumps. Experimental Apparatus and Flow Patterns

ASCE Journal of Hydraulic Engineering, 1995

In open channels, the transition from supercritical to subcritical flows is called a hydraulic jump. For low upstream Froude numbers, free-surface undulations develop downstream of the jump and the hydraulic jump is called an undular jump. New experiments on undular hydraulic jumps were performed in a rectangular channel in which the upstream flows were fully developed turbulent shear flows. In this paper, the main flow patterns are described. Visual and photographic observations indicate five types of undular jumps. One of the main flow characteristics is the presence of lateral shock waves for Froude numbers larger than 1.2. The results show that the disappearance of undular jump occurs for Froude numbers ranging from 1.5 to 2.9, and the wavelength and amplitude of free-surface undulations are functions of the upstream Froude number and the aspect ratio y)W.

Hydraulic Jump: A Brief History and Research Challenges

Water, 2021

This paper presents a brief history of the hydraulic jump and a literature review on hydraulic jumps’ experimental and numerical studies. Leonardo da Vinci noticed this phenomenon early on, but it was only later studied by Bidone in 1820. Since the beginning of the 20th century, the hydraulic jump has received a lot of attention following the development of energy dissipater designs and stilling basins. The late 1920s and early 1930s saw many experimental studies researching the surface roller profile and energy dissipation. The study of internal flow features started in the late 1950s. Starting in the 70s, it was believed that the flow of a jump must be analyzed in its actual configuration of air–water mixture, an aspect that cannot be overlooked. Several experimental studies in the late 1980s and 1990s highlighted the existence of oscillating phenomena under specific flow conditions and particularly, a cyclic variation of jump types over long-lasting experiments. The early 2000s s...

Experimental Simulation of Hydraulic Jump for the Study of Sequent Depth Using an Obstruction

Advances in transdisciplinary engineering, 2022

Hydrological jump characteristics in a rectangular open channel flume with sluice gates at both ends are the focus of this article. Among the many aspects of hydraulic jump that have been examined analytically and experimentally are: (i) Sequent depth relation (), (ii) Length of the jump, (iii) Relative loss of energy (), (iv) Water profile of the jump. There was a total of 15 inflow tests conducted. With values between 1.5 and 1.7, Froude's number displays considerable variation. The results show that when the slope increases, the sequent depth ratio, leap length, and Relative energy loss all decrease. The fluctuation of the relative energy loss () with Pre-jump Froude's number (F1) for different slopes is also indicated by the graph. The graph also depicts the water profile of the leap. Continuous flow is shown by the relatively uniform discharge at each location.

Experimental observations on undular hydraulic jumps with very high aspect ratio

Experimental data regarding jumps with very high aspect ratios are very rare in literature, therefore experimental works are necessary. The present paper analyses the formation of undular hydraulic jumps in a very large channel, characterized by a 4.0 m width, for low Reynolds number. Once observed that the investigated jumps were characterized by the formation of lateral shock waves, the purpose of the present work is both to analyse the flow conditions of undular jumps and to verify the experimental validity of the classic shock wave theory in very large channels. Seven experimental tests were carried out and their results can be summarized in the following way: (i) the presence of well developed lateral shock waves similar to those of oblique jumps were observed; (ii) the comparison of the experimental and the theoretical data show that the classical shock wave theory is confirmed, taking into account the experimental errors; (iii) the literature law of the wave height of first w...

The hydraulic jump and the shallow-water equations

International Journal of Advances in Engineering Sciences and Applied Mathematics, 2011

This is a study of the shallow-water equations in the context of standing hydraulic jumps in a planar geometry. The inviscid solutions are reviewed and it is demonstrated that the commonly used vertical averaging procedure leads to a closure problem. Inconsistencies associated with the vertical averaging procedure are also pointed out. We thus show that the recent solutions of the boundary-layer shallow-water equations provided in Dasgupta and Govindarajan (Phys Fluids 22:108-112, 2010) are consistent and correct.

Landscapes of Water, History, Innovation and Sustainable Design (original) (raw)

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