Hydraulic Jump


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Hydraulic jump

An abrupt increase of depth in a free-surface liquid flow. A hydraulic jump is characterized by rapid flow and small depths on the upstream side, and by larger depths and smaller velocities on the downstream side. A jump can form only when the upstream flow is supercritical, that is, when the fluid velocity is greater than the propagation velocity c of a small, shallow-water gravity wave (c = gh, where g is the acceleration of gravity and h is the depth). A considerable amount of energy is dissipated in the conversion from supercritical to subcritical flow. See Open channel

McGraw-Hill Concise Encyclopedia of Physics. © 2002 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Hydraulic Jump

 

an abrupt turbulent rise in water level in an open channel during a change in flow from a so-called turbulent condition to a calm condition. Hydraulic jump is accompanied by the formation of a surface “roller,” within which the heavily air-saturated fluid is in compound rotary motion.

Hydraulic jump usually occurs during the passage of a flow through the openings of hydraulic structures, such as spillways and floodgates. Channel degradations can occur as a result of high flow rates along the bottom in the hydraulic jump zone. The theory of hydraulic jumps is treated in hydraulics.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

hydraulic jump

[hī′drȯ·lik ′jəmp]
(fluid mechanics)
A steady-state, finite-amplitude disturbance in a channel, in which water passes turbulently from a region of (uniform) low depth and high velocity to a region of (uniform) high depth and low velocity; when applied to hydraulic jumps, the usual hydraulic formulas governing the relations of velocity and depth do not conserve energy.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

hydraulic jump

hydraulic jump
A phenomenon at the transition from high to low velocity in the horizontal pipe at the base of a vertical drain (i.e., a drainage stack) where the flow of water changes from a vertical to horizontal direction; results in a discontinuity in flow at a short distance downstream from the base of the drainage stack. (See illustration p. 524.)
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
References in periodicals archive ?
Experimental study of the air-water shear flow in a hydraulic jump, International Journal of Multiphase Flow 26: 583-607.
If a hydraulic jump occurs in the conduit, the local air entrainment is due to surface and velocity discontinuity characterized by intensive turbulence productions [2-4].
The hydraulic jump with sudden enlargement and drop was commonly used to be an energy dissipator in hydraulic engineering and it is actually a kind of submerged offset jet.
This phenomenon is known as an oblique hydraulic jump. It has been considered to confirm the capability of handling high-speed discontinuous flows and the stability under a supercritical flow situation.
By running the CFD simulation on a 32-core cluster computer and repeating the simulation multiple times using different river conditions, the designers discovered the maximum hydraulic jump that could occur.
Brattberg, "Experimental study of the air-water shear flow in a hydraulic jump", Int.
Excessive retrogression and consequently the sweeping of hydraulic jump were noted as the main reasons for the damages.
Civil engineering applications are described, including air quality prediction, finite-element model updating, hydraulic jump, and seismic attenuation relationships.
The undular hydraulic jump in turbulent open channel flow at large Reynolds numbers.
(4) Professor, Women's College, Gulbarga, India Table 1: Analogous quantities of classical hydraulic analogy 2D gas flow Free Surface incompressible water flow Temperature ratio T/T0 Hydraulic depth ratio h/h0 Density ratio Hydraulic depth ratio h/h0 Pressure ratio P/P0 Sq of hydraulic depths ratio (h/h0)2 Sound Velocity a0 Wave Velocity _(gh) Mach number V/ a0 Froude number V/_(gh) Velocity ratio V/Vmax Velocity ratio V/ Vmax Subsonic flow M<1 Streaming Water flow Fr<1 Supersonic flow M>1 Shooting Water Flow Fr>1 Compressible shock Hydraulic jump