B-jump in sloping channel, II

Kawagoshi, N.; Hager, W.H.

doi:10.1080/00221689009499060

Cited by 56 publications

(31 citation statements)

References 4 publications

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“…As Q increases, the upstream Froude number becomes larger, and the katabatic jump becomes stronger. This parametric dependence of the katabatic jump strength on upstream mean Froude number is also common to hydraulic jumps in open channel flows, in which the strength of the hydraulic jump increases with the approach Froude number (e.g., Kawagoshi and Hager, 1990). The scale used for the katabatic jump strength in Figure 6a is similar to that used for tra- ditional hydraulic jumps, while that used in Figure 6b is more suitable for meteorological applications.…”

Section: Sensitivity Experimentsmentioning

confidence: 94%

Numerical simulations of katabatic jumps in coats land, Antartica

Cai

King

et al. 2005

Boundary-Layer Meteorology

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A non-hydrostatic numerical model, the Regional Atmospheric Modeling System (RAMS), has been used to investigate the development of katabatic jumps in Coats Land, Antarctica. In the control run with a 5 m s À1 downslope directed initial wind, a katabatic jump develops near the foot of the idealized slope. The jump is manifested as a rapid deceleration of the downslope flow and a change from supercritical to subcritical flow, in a hydraulic sense, i.e., the Froude number (Fr) of the flow changes from Fr > 1 to Fr < 1. Results from sensitivity experiments show that an increase in the upstream flow rate strengthens the jump, while an increase in the downstream inversion-layer depth results in a retreat of the jump. Hydraulic theory and Bernoulli's theorem have been used to explain the surface pressure change across the jump. It is found that hydraulic theory always underestimates the surface pressure change, while Bernoulli's theorem provides a satisfactory estimation. An analysis of the downslope momentum balance for the katabatic jump indicates that the important forces are those related to the pressure gradient, advection and, to a lesser extent, the turbulent momentum divergence. The development of katabatic jumps can be divided into two phases. In phase I, the pressure gradient force is nearly balanced by advection, while in phase II, the pressure gradient force is counterbalanced by turbulent momentum divergence. The upslope pressure gradient force associated with a pool of cold air over the ice shelf facilitates the formation of the katabatic jump.

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Section: Sensitivity Experimentsmentioning

confidence: 94%

Numerical simulations of katabatic jumps in coats land, Antartica

Cai

King

et al. 2005

Boundary-Layer Meteorology

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“…For hydraulic jumps, a more efficient stilling basin can be obtained if the sequent depth is lower, the roller length is shorter, and the energy loss in the jump is greater than that in the classical jump. Extensive work has been done in the past on the jumps forming on mild, steep positive, and adverse slopes that were classified by Kindsvater (1944) and Rajaratnam (1966) into jump types A, B, C, D, E, and F. Kindsvater (1944), Bradley and Peterka (1957), Rajaratnam (1966), Hager (1988), Kawagoshi and Hager (1990), Ohtsu and Yasuda (1991), and McCorquodale and Mohamed (1994) are among the many researchers who have undertaken valuable investigations in this field. However, most of these studies dealt with only one specific type of jump.…”

Section: Introductionmentioning

confidence: 98%

Hydraulic jump in sloping channels: roller length and energy loss

Beirami

Chamani

2010

Can. J. Civ. Eng.

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This paper deals with the roller length and energy loss of a large variety of hydraulic jumps in horizontal and sloping channels. The supercritical upstream flow originated from a standard ogee weir. A stilling basin with bottom slopes of 0.0, -0.025, -0.050, -0.075, and -0.100 was used to generate the jumps. Based on the energy principle, a semiempirical method to predict the roller length is presented. Predictions based on the proposed method agree well with the results reported by the authors and other researchers. It is shown that the energy loss in the classical jump is greater than that in any jump forming on negative or positive slopes.Résumé : Cet article traite de la longueur des rouleaux et de la perte d'énergie d'une grande variété de ressauts hydrauliques dans les canaux horizontaux et en pente. L'écoulement surcritique en amont provenait d'un déversoir en doucine standard. Un bassin de tranquillisation muni de pentes de fond de 0,0, -0,025, -0,050, -0,075 et -0,100 a été utilisé pour générer les ressauts. Une méthode semi-empirique basée sur le principe de l'énergie est présentée afin de prévoir la longueur des rouleaux. Les prévisions basées sur la méthode proposée concordent bien avec les résultats rapportés par les auteurs et d'autres chercheurs. Il a été démontré que la perte d'énergie dans le ressaut hydraulique conventionnel est supérieure à celle de tout ressaut se formant sur des pentes négatives ou positives.Mots-clés : ressaut hydraulique, canal en pente, pente inverse, longueur de rouleau, perte d'énergie.[Traduit par la Rédaction]

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“…Hager (1988) investigated Bjumps in a channel with a=45° and Kawagoshi and Hager (1990) extended the previous findings to a=30°. According to these Authors, the sequent depth ratio depends on the channel slope, the approach flow Froude number:…”

Section: Introductionmentioning

confidence: 94%

Sequent depth ratio of B-jumps on smooth and rough beds

Carollo

Ferro

Pampalone

2013

J Agricult Engineer

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A hydraulic B-jump has the toe section located on a positively sloping upstream channel and the roller end on a downstream horizontal channel. This paper analyses the B-jump on a rough bed, such as at the transition from a block ramp to the stilling basin. Laboratory measurements of the sequent depth were carried out using three different channel slopes for the rough bed and a single slope for the smooth bed. A solution useful for estimating the sequent depth ratio in a rectangular channel for different relative roughness and bed slope is proposed and positively tested by the present measurements. This solution can also be used to estimate the sequent depth ratio of classical hydraulic jumps or B-jumps on smooth and rough beds.

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B-jump in sloping channel, II

Cited by 56 publications

References 4 publications

Numerical simulations of katabatic jumps in coats land, Antartica

Numerical simulations of katabatic jumps in coats land, Antartica

Hydraulic jump in sloping channels: roller length and energy loss

Sequent depth ratio of B-jumps on smooth and rough beds

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