Experimental Study on the Time Development of Local Scour on Around Single T-Shape Spur Dike in a 180 Degree Flume Bend

Masjedi, Alireza; Bejestan, Mahmood Shafai; Rahnavard, P.

doi:10.3923/rjes.2010.530.539

Cited by 15 publications

(9 citation statements)

References 9 publications

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“…But for run 4, more amount of scour occured as compared to run 2 and run 3 as the Froude number was more. This finding is in agreement with the results of Ghodsian andVaghefi (2009) andMasjedi et al(2010a) where they observed that the vortex and scour increases with the increase in Froude number. Again, at 30⁰ azimuthal section maximum amount of scour occured at the outer bank of the channel and a good amount of depositions were seen at 80⁰ section along the inner bank.…”

Section: Scour At Bendsupporting

confidence: 94%

Experimental Study on Scour at 90° Horizontal Forced Bend and its Protection Using Riprap

Biswas

Barbhuiya

2015

Aquatic Procedia

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Experimental investigations were done to study the scour at bend and its protection using stone riprap. The experiments were carried out in a 90° horizontal bend flume with non-cohesive bed sediments having median diameter 0.34 mm and 1.18 mm. The cross-section of flows was made trapezoidal in shape with sediments at the bottom and sides. The results of the present study indicate that the scour occur mainly at the outer bank of the 90º horizontal bend. Maximum scour and deposition occur around 30⁰ azimuthal section near the concave and convex bank respectively. Upstream at the 0⁰ section, small scour near the inner bank was observed. These may be due to cross current towards the concave bank. Along downstream, the depth of scour increases near the concave bank and reaches its maximum value around the 30⁰ section. Further downstream, the depth of scour decreases along concave bank but little scour was noticed along the convex bank downstream of 70⁰ section. On the other hand, the deposition occur near the lower part of convex bank from 20⁰ to 60⁰. There exists a transverse slope of the water surface across the section with higher level at the concave side. As a result of this transverse slope, the bottom water moves from the concave bank to the convex bank whereas, the surface water moves from convex to concave. It also carries with it the bed material and deposits it near the convex bank, Further, it is found that flexible riprap placed on the sloping bank extending little beyond the toe can be used to protect the bend erosion due to flow. The data obtained in the experimental investigation will be useful for the proper design of protection works at bends.

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Section: Scour At Bendsupporting

confidence: 94%

Experimental Study on Scour at 90° Horizontal Forced Bend and its Protection Using Riprap

Biswas

Barbhuiya

2015

Aquatic Procedia

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“…Referring to three typical stages of local scour evolution [27,28]: The initial stage of the local scour, the ratio of τb/τc is 4.5 from the upper limit, close to the results discussed in the literature [14], and rapidly decline to 1.0, which indicates that the local bed shear stress decreases rapidly. Dodaro et al [29] also demonstrates a rapid decrease of bed shear stress with temporal evolution of the scour hole during the initial phase of scour development.…”

Section: The Local Bed Shear Stress Evolutionsupporting

confidence: 81%

The 3-D Morphology Evolution of Spur Dike Scour under Clear-Water Scour Conditions

Zhang

Wang

Zhang

et al. 2018

Water

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By changing the alignment angle of spur dike, this study focused on the evolution of scour hole morphology in three alignments under clear-water scour conditions, including the 3-D structure of the scour hole, 2-D profile morphological evolution process and the evolution characteristics of the local bed shear stress. The results show that the plane area and volume of the scour hole both are power functions over time, which is similar to the evolution characteristics of scour depth. Local scour includes three stages: The initial stage, development stage and balance stage. The local bed shear stress presents successively: τb > τc, τb = τc and τb < τc. Based on this characteristic, the evolution mechanism between scour hole morphology and the local bed shear stress is further clarified. Furthermore, although the alignment of the spur dike significantly affects the longitudinal and vertical dimension erosion rates of the scour hole, the scour hole morphology is not only relatively constant but also has a specific proportion, and the evolution process is orderly in the whole process of evolution. To the scouring equilibrium state, the length of the scour hole on the upstream and downstream of the spur dike is approximately in line with the golden section feature. The related results provide technical support for scour parameter design and scour hole protection of spur dike in flood period.

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“…The maximum scour depth was located at the upstream nose of spur dike at a distance of about 10-20% of the spur dikes length. Masjedi, Dehkordi et al (2010) conducted laboratory experiments to study the effect of Froude number, location and length of spur dike on scour depth around spur dike installed at 180°channel bend. It was found that the scour depth increases with the increase in the Froude number and length of spur dike, but it decreases with increase in wing length of spur dike.…”

Section: Brief Reviewmentioning

confidence: 99%

Influence of cohesion on scour around submerged dike founded in clay–sand–gravel mixtures

Lodhi

Jain²,

Sharma

2015

ISH Journal of Hydraulic Engineering

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This study presents the influence of cohesion on scour depth around submerged spur dike founded in the mixtures of cohesive sediment consisting of clay-gravel and clay-sand-gravel. Studies related to scour around submerged dike founded in such type of cohesive sediment mixtures are not reported in the literature to best of our knowledge. All experiments were conducted with singular submerged spur dike under clear water flow conditions. The process of scour around submerged spur dike founded in clay-gravel/clay-sand-gravel mixtures was found significantly different from that of cohesionless sediments. The process, geometry and scour depth around submerged spur dike in cohesive sediments were significantly affected by clay percentage and unconfined compressive strength of cohesive sediment mixtures. Relationships are proposed for the assessment of scour depth at nose and, at the wake of submerged spur dike in cohesive sediments mixtures. The proposed relationships give satisfactory agreement between observed and calculated values.

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Experimental Study on the Time Development of Local Scour on Around Single T-Shape Spur Dike in a 180 Degree Flume Bend

Cited by 15 publications

References 9 publications

Experimental Study on Scour at 90° Horizontal Forced Bend and its Protection Using Riprap

Experimental Study on Scour at 90° Horizontal Forced Bend and its Protection Using Riprap

The 3-D Morphology Evolution of Spur Dike Scour under Clear-Water Scour Conditions

Influence of cohesion on scour around submerged dike founded in clay–sand–gravel mixtures

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