Hydraulic jump experiment in a rectangular open channel flume. From there the momentum equation, and the conjugate depths equation can be derived. Momentum considerations in hydraulic jumps and bores hubert chanson1 abstract. The hydraulic jump in circular jet impingement and in other thin liquid films x. You will be introduced to the hydraulic phenomenon known as the hydraulic jump the sudden transition from a higher energy state to a lower energy state constrained by the conservation of momentum analogous to a shock wave. They studied the momentum, the length of the hydraulic jump, and the energy dissipation by the numerical model, and then compared the results with the experimental data. Hydraulic jump in a rectangular channel, also known as classical jump, is a natural. To do this it is necessary to include the conservation of angular momentum. The water changes its state from super critical to subcritical in very shorter length when compared to all other types of hydraulic jumps, so this jump is highly preferred in dam structures. Lienhard v department of mechanical engineering, massachusetts institute of technology, cambridge, ma 029 usa received.
Hydraulic jump a rectangular horizontal channel 2m. However, in the absence of a precise theory of velocity distribution, an. The most common application of the momentum equation in openchannel flow deals with the analysis of the hydraulic jump. This experiment illustrates the behavior of supercritical flow under sluice gate for various flow rates and downstream depths. The verniers are zeroed with the bed of the channel and have to be moved depending on the location of the hydraulic jump. To describe the jump condition, consider the hydraulic jump shown in the figure. Jun 19, 2016 in an open channel when rapidly flowing stream abruptly changes to slowly flowing stream, a distinct rise or jump in the elevation of liquid surface takes, this phenomenon is known as hydraulic jump. In the application of the energy and momentum principles in pipes and channels, standard hydraulic practice is to assume that the velocity is constant across a section and to ignore the fact that there are boundary layers on all solid surfaces. The authors then defined the end of the hydraulic jump as l j 8. The analysis is based on depth averaged reynolds momentum equations.
The application of the equations of conservation of mass and momentum in their integral form yields a series of relationships. Hydraulic jump momentum equation cv supercritical flow f1 subcritical flow f momentum equation is applied. The hydraulic jump is the sudden transition from a highvelocity open channel. Hydraulic jump types and characteristics of hydraulic jump. Although momentum is conserved throughout the hydraulic jump, the energy is not. The mean vorticity increases from zero as the cube of froude number minus one, and. Despite the fact that there is an energy loss, momentum across a hydraulic jump is still conserved.
When liquid at high velocity discharges into a zone of lower velocity, a rather abrupt rise occurs in the liquid surface. Hydraulic jump module9 for class university of alabama. Conservation of mass, momentum, and energy in a sluice gate. Hydraulic jump keith bechtol october 31, 2007 submitted as coursework for physics 210, stanford university, fall 2007 introduction. Conservation of momentum is advantageous in this situation because momentum cannot be lost from internal friction, only through external forces on the water e. Introduction to openchannel flow 1 david apsley part 2. Geomorphology of natural c hannels concerns their shape and structure. Conservation of mass, momentum, and energy in a sluice gatehydraulic jump flow purpose to demonstrate conservation of mass, momentum, and energy equations in sluice gatehydraulic jump flow. Basic hydraulic principles of openchannel flow by harvey e. The flow field downstream of a hydraulic jump core. Open channel flow geomorphology of natural channels. The depth water on the downstream side of the hydraulic jump is 1m. The sensor was moved along the longitudinal axis of the channel. Hydraulic jumps often occur when there is a conflict between the upstream and downstream controls.
Hydraulic jump experiment in a rectangular open channel. Linear and angular momentum conservation for the hydraulic. Characteristics of the hydraulic jump in trapezoidal channel. Froehlich abstract the three basic principles of openchannelflow analysis the conserva tion of mass, energy, and momentum are derived, explained, and applied to solve problems of openchannel flow. The hydraulic jump a hydraulic jump results when there is a conflict between upstream and downstream control. A hydraulic jump occurs in open channel flow whenever supercritical flow froude number greater than one occurs on a slope that isnt steep enough to maintain that supercritical flow. Linear and angular momentum conservation in hydraulic jump in diverging channels. A related process is the hydraulic jump in translation. For a given value on m there are in general two possible water depths sequent depths of a hydraulic jump. Current knowledge in hydraulic jumps and related phenomena. In a hydraulic jump a large amount of energy is lost as heat in the turbulence of the jump. Consequently, in a crosssection with unequal velocities, the momentum surges greatly. Hydraulic jump experiment laboratory practical manual notes. Pdf hydraulic jumps in adverseslope stilling basins for.
One vernier is located upstream of the hydraulic jump to measure the supercritical depth, y1, and the other downstream of the hydraulic jump to measure the subcritical depth, y2. The hydraulic jump as a transition from subcritical to. This note is the final completion of a previously published work concerning the integral conservation of linear and angular momentum in the steady hydraulic jump in a linearly diverging channel. To demonstrate conservation of mass, momentum, and energy equations in sluice gatehydraulic jump flow. This paper presents a laboratory experiment for the formation of hydraulic jump in a rectangular open channel flume to accurately explore the effect of flow structures on water resources. However, because momentum is conserved across hydraulic jumps under the assumptions of this study, momentum theory. Basic sketch of momentum equation for the hydraulic jump on rough bed of channel with expanding walls. This process is often accompanied by extreme turbulence and high energy losses. Strong decelerations to the upper level jet is verified. A textbook of fluid mechanics by dr rk bansal is available at. There is an initial loss of energy when the flow jumps from supercritical to subcritical depths. This method can be recognized as a particular case of the solution of the momentum integral equation used extensively in. Hydraulic jumps and the momentum principle hydromechanics vvr090 ppt by magnus larson. A hydraulic jump is a good way of destroying surplus energy in reality, converting kinetic energy to heat and is often deliberately introduced for that purpose, such as at the foot of a dam spillway or downstream of a control gate.
Mar 25, 2019 a textbook of fluid mechanics by dr rk bansal is available at. Due to this there is a loss of kinetic energy the hydraulic. A hydraulic jump is a fluid shockwave created at the transition between laminar and turbulent flow. Strong jump is a perfect jump formed when frictional losses are more, air pressure division is equal and velocity is very high that losses take place. Calculations for typical parameters in simple hydraulic jumps in rectangular channels energy loss. Specific momentum curve analogous to the specific energy curve. A hydraulic jump is the turbulent transition from a high velocity into a slower flow. Hydraulic jump and resultant flow choking in a circular. This means that the flow depth on either side of the jump will have the same momentum, and in this way, if the momentum and flow depth on either side of the jump is known, it is possible to determine the depth on the other side of the jump. Pdf the streamwise flow structure of a turbulent hydraulic jump over a rough bed.
Momentum considerations in hydraulic jumps and bores pdf. Test design the force on a sluice gate in an open channel is determined by two methods. June 29, 2017 4548 validation of the hydraulic jump model the experimental work was accomplished in the laboratory to explore the critical depth and the conjugate depths of hydraulic jump as shown in igures 3,4. You will be introduced to the hydraulics phenomenon known as the hydraulic jump see figure 1 the sudden transition from a higher energy state to a lower energy state while conserving momentum analogous to a shock wave in compressible gas flows. Momentum principle because of energy losses, the size and location of the hydraulic jump cannot be predicted using the energy equation. If a, the relative height of the submerged j u m p, is defined by the equation c t 3 co 35 then it can be shown that co 36 w y y y y, s r 3 2 s fig. A hydraulic jump is a phenomenon in the science of hydraulics which is frequently observed in open channel flow such as rivers and spillways. Jan 06, 2017 hydraulic jump formulas in terms of froudenumber 3. In this transition, the water surface rises abruptly, surface rollers are formed, intense mixing occurs, air is entrained, and often a large amount of energy is dissipated. Hydraulic jump in a rectangular channel, also known as classical jump, is a natural phenomenon that occurs whenever flow changes from supercritical to subcritical flow. Pdf analysis of turbulent hydraulic jump over a transitional. An experimental study of hydraulic jump in a gradually expanding. The hydraulic jump and its types are defined and classified.
If upstream control induces supercritical flow and downstream control induces subcritical flow. The hydraulic jump in circular jet impingement and in other. Details of hydraulic jumps for design criteria of hydraulic. The hydraulic jump converts kinetics energy of rapidly flowing into potential energy.
The minimum value of m corresponds to the minimum value of e. Momentumdepth relationship in a rectangular channel wikipedia. Pdf linear and angular momentum conservation for the hydraulic. Theoretically, hydraulic jump controlled by sills can be interpreted using the momentum theory. Apr 15, 2018 hydraulic jump in civil eng this feature is not available right now. Natural channels are of irregular shape, varying from.
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