Influence of tailwater depth, sediment size and densimetric Froude number on scour by submerged square wall jets

Sarathi, Partha; Faruque, Md Abdullah Al; Balachandar, Ram

doi:10.1080/00221686.2008.9521853

Cited by 33 publications

(43 citation statements)

References 16 publications

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“…3(b) it is evident that the relative scour hole lengths l s /D and l h /D decrease with increasing F i but increase with increasing F w . This trend for the single wall jet is in line with Ali and Lim (1986) and Sarathi et al (2008), but not for the scour due to single impinging jet made by Aderibigbe and Rajaratnam (1996). The impinging jet behaves like an obstacle for the development of the wall jet.…”

Section: Observationssupporting

confidence: 61%

“…The effect of the expansion ratio on the scour depends also on the range of the other non-dimensional parameters, explaining the differences between Lim (1995) and Sui et al (2008). Ali and Lim (1986), Lim (1995), Aderibigbe and Rajaratnam (1996), Sarathi et al (2008), and Sui et al (2008) demonstrated that the scour depth and length increase with the densimetric Froude number. Figure 3(a) confirms this trend for the scour depth due to the two jets.…”

Section: Observationsmentioning

confidence: 99%

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Scour formation due to simultaneous circular impinging jet and wall jet

Mehraein

Ghodsian

Schleiss

2012

Journal of Hydraulic Research

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Experiments involving both a circular wall jet and an impinging jet were conducted, as occurring at irrigation control structures or at dams with combined crest and low-level spillways. The effects of the non-dimensional parameters on the scour hole dimensions have been investigated. It was found that the effect of the expansion ratio of the channel width to the jet diameter is negligible for values larger than 22.5 and 35, depending on the experimental conditions. The scour depth decreases with increasing tailwater depth and the horizontal distance between the impinging jet and the origin of the wall jet. The scour length and the distance between the end of the ridge and the wall jet origin increase with decreasing densimetric Froude number of the impinging jet. The opposite trend occurs for decreasing densimetric Froude number of the wall jet. An empirical relationship for estimating the scour depth due to the simultaneous jet action is given.

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Section: Observationssupporting

confidence: 61%

Section: Observationsmentioning

confidence: 99%

Scour formation due to simultaneous circular impinging jet and wall jet

Mehraein

Ghodsian

Schleiss

2012

Journal of Hydraulic Research

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“…When analyzing the data collected from their experiments, they noticed the existence of a critical value of tailwater depth minimizing the maximum scour depth and a limit value beyond which the maximum scour depth depended on the jet densimetric Froude number only. Similar conclusions regarding tailwater depth have been drawn also by Sarathi et al (2008), even though their observations regarding the tailwater depth limit value are quantitatively different from the ones made by Ali and Lim (1986). Johnston (1990), when carrying out experiments on plane jets on mobile beds identifi ed three different scourhole regimes: one when the jet stays attached to the surface, one where it stays attached to the bed and another one where it oscillates periodically between these two confi gurations, without reaching a steady asymptotic state.…”

Section: Introductionsupporting

confidence: 56%

“…The existence of a such conditions has been reported by other authors before (Ali and Sarathi et al 2008). The existence of a similar critical value also in jet inclination is possible; further developments regarding the validity of this assumption are in progress.…”

Section: Discussionmentioning

confidence: 51%

“…By using dimensional analysis (Ali and Lim 1986;Johnston 1990;Rajaratnam 1981) and using y 1 as a length scale, the generic scaled problem feature N Φ can be represented as a function of non dimensional parameters in the following way: Some authors reported the infl uence of relative roughness y 1 /D to be negligible (Chatterjee et al 1994;Rajaratnam 1981;Sarathi et al 2008) at least when the steady state of the scour is approached. In our tests, relative roughness is very low, if compared to similar studies, ranging between 1.78 and 3.97.…”

Section: Dimensional Analysismentioning

confidence: 99%

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On the erosion due to inclined jets

Minatti

Paris²,

Solari³

2010

Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation

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On the erosion due to inclined jets.Some preliminary experiments and studies regarding scour processes on a mobile bed caused by inclined jets issuing from a sluice gate are presented. Tests with submerged tailwater conditions have been carried out using different fl ow and geometric conditions. The investigated experimental conditions included different jet Froude numbers, inclinations and tailwater conditions. The bed confi guration has been measured during the whole scour hole evolution process until the achievement of a dynamic steady state, where sediment motion was still possible even though it did not allow for any persistent change in the scour and ridge shapes anymore. On the basis of the observed sediment motion, two different patterns of fl ow seem to develop under the investigated conditions: one where the main fl ow remains attached to the bottom of the channel and another where it oscillates between the aforementioned confi guration and a surface jet. Some relevant parameters have been identifi ed and used to plot graphs showing their correlation and trends.

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