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Ananth Wuppukondur

Other affiliations: University of Queensland
Bio: Ananth Wuppukondur is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Geology & Pile. The author has an hindex of 3, co-authored 4 publications receiving 15 citations. Previous affiliations of Ananth Wuppukondur include University of Queensland.

Papers
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Journal ArticleDOI
TL;DR: In this article, vanes and circular piles are proposed as scour mitigation measures in a distorted mobile bed model with 90° confluence angle and three discharge ratios (Qr = 0.33, 0.50 and 0.75) are used.
Abstract: Confluence is a common occurrence in rivers. The convergence of flows often leads to erosion of the river bed and formation of a deep scour-hole at the confluence. In the present experimental study, vanes and circular piles are proposed as scour mitigation measures. Experiments are performed in a distorted mobile bed model (d50 = 0.28 mm) with 90° confluence angle. Three different discharge ratios (Qr = ratio of lateral to main flow discharge) of 0.33, 0.50 and 0.75 are used. Vanes (1.5 cm width and 1 mm thick) or piles (ɸ = 8 mm and 12 mm) are arranged in a row perpendicular to the lateral flow at a spacing of 5, 10 or 15 cm. Three vane angles of 15°, 30° and 60° with respect to the main flow are used. The experimental results show that scour depth (Sd) increases with an increase of Qr. Sd reduces by 33%, 50% and 47% with vanes for Qr = 0.33, 0.50 and 0.75, respectively. Sd reduces by 43%, 55% and 55% with 12 mm piles and by 70%, 60% and 59% with 8 mm piles, for the corresponding discharge ratios...

9 citations

Journal ArticleDOI
TL;DR: In this paper, experiments were conducted to control sediment entry into an intake channel using submerged vanes in a physical model with a rectangular mobile-bed main channel and a trapezoidal rigid-bed intake channel diverting at an angle of 45°.
Abstract: Intake canals are used to withdraw water from rivers for various purposes. Sedimentation in the intake canal reduces the quality and quantity of water being delivered. In this study, experiments were conducted to control sediment entry into an intake channel using submerged vanes in a physical model with a rectangular mobile-bed main channel and a trapezoidal rigid-bed intake channel diverting at an angle of 45°. The variables in the study included vane angle, number of vane rows, and vane spacing in terms of mean flow depth in the main channel. In addition to the commonly used vane array with uniform vane heights, three other vane-height configurations were also tested. The least local scour around vanes and highest sediment reduction (~70%) were observed for vanes oriented at a 15° vane angle with an increasing vane-height configuration placed in two rows. It was also observed that control of sediment entry into the intake canal increased with an increase of both vane spacing and number of vane rows.

7 citations

Journal ArticleDOI
TL;DR: In this article, the authors used a distorted model with a non-uniform sediment of mean particle size d¯¯ 50672 ǫ = 0.28mm with a confluence angle of 60°.
Abstract: River confluences have complex hydrodynamics than ambient flows due to different flow characteristics of the two merging flows. Secondary circulation develops due to merging of two flows which leads to bed erosion. The eroded sediment gets deposited at various locations in the downstream of the confluence. It is reported in the literature that major reservoirs in India will lose 50% storage capacity by 2020 and reservoirs all over the world lose storage capacity by as much as 5% every year. In view of controlling bed erosion at the confluence, vane and circular pile models are used as scour mitigation structures and experimental results are presented. Experiments are performed in a distorted model with a non-uniform sediment of mean particle size d 50 = 0.28 mm with a confluence angle of 60°. Two different discharge ratios (Q r = ratio of lateral flow discharge to main flow discharge) of 0.5 and 0.75 are used with a constant flow depth (H m) of 5 cm in the main channel. Vanes of width 0.3H m (1.5 cm), thickness of 1 mm are placed at 15°, 30° and 60° vane angles with respect to main flow. Circular pile models of 8 and 12 mm diameter are also used. Two different spacing of 2H m and 3H m (10 and 15 cm) between the vanes or piles are used to perform the experiments. For Q r = 0.5 and 0.75 using vanes, scour depth reduces by 25 and 34%, respectively. When circular pile models of 8 and 12 mm are used, the scour depth reduces by 25, 38 and 27, 43%, for Q r = 0.5 and 0.75, respectively. The scour depth decreases with an increase of vane angle and pile diameter, but increases with an increase of spacing. Therefore, piles have better performance over vanes in reducing scour at the confluence.

4 citations

Journal ArticleDOI
TL;DR: In this paper , the authors evaluated the performance of current numerical models that are employed in various tsunami warning centres across the world, in terms of their accuracy for the prediction of tsunami wave characteristics in converging channels.

1 citations

DOI
21 Feb 2022
TL;DR: In this paper , the authors studied the protection of coastal dunes against tsunamis by using laboratory experiments on a laboratory scale model of the dune (rigid surface) on different plane beach slopes.
Abstract: Tsunamis are one of the most disastrous natural hazards and have a high potential to devastate coastal infrastructure which can result in a notable loss of life. When tsunami waves approach the coast, they cause runup, overtopping, and inundation, which can damage coastal infrastructure and pose a threat to human lives. The tsunami runup is an important factor in the design of coastal protection structures against tsunamis. Therefore, it is essential to predict the runup height of tsunami waves accurately and quickly. From the field observations of past tsunami events at many parts of the world, it was identified that the coastal features like dunes, dense vegetation, and combination of dunes with vegetation, acted as natural buffers and provided protection to the regions behind those coastal features [1]-[6]. In order to study the protective behavior of coastal dunes against tsunamis, laboratory experiments were conducted on a laboratory scale model of the dune (rigid surface) on different plane beach slopes (s) (s= 1/2, 1/5, 1/15 & 1/20). The maximum solitary wave runup (R) was observed on the steep beach slope (s=1/2, non-breaking wave) and the minimum runup was observed on the mild beach slope (s=1/20, breaking wave) in the range 0.05

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01 Jan 2004
TL;DR: In this article, a simple one-dimensional formulation was proposed to predict the transitional flow at an open-channel junction, based on energy and continuity equations, and an empilical relation between the junction losses, the junction angle, and the discharge ratio was suggested which agrees well with the experimental results.
Abstract: On the basis of energy and continuity equations a simple one-dimensional formulation was proposed to predict the transitional flow at an open-channel junction. An empilical relation between the junction losses, the junction angle, and the discharge ratio was suggested which agrees well with the experimental results. The results calculated by the present formulation for the depth ratio were compared with the results of earlier one-dimensional formulations and experiments. It is found that the present results coincide better with experiments than those of others.

24 citations

Journal ArticleDOI
TL;DR: In this article, a study was conducted at the point of convergence of the River Deo with the River Manu using simple geospatial technique and field work to justify the hydrological and morphological changes in downstream of the confluence point.
Abstract: Tributaries play a significant role in changing flow structure of the main river through their additional discharge. A study was conducted at the point of convergence of the River Deo with the River Manu using simple geospatial technique and field work to justify the hydrological and morphological changes in downstream of the confluence point. The spatio-temporal change of both the river channels for 10 km length in upstream and downstream of the confluence point was considered. Moreover, field measurements and post-field work were carried out to examine the spatial variation of hydrodynamic characteristics like flow velocity, depth, water discharge, wetted perimeter and hydraulic radius of the selected stretches. Sieving method was applied for grain size analysis of river bed sediment samples. The result revealed that both the aggradation and degradation processes were equally active in the upstream segment of the Manu River but in downstream segment aggradation exceeded the degradation activity, though all the hydrodynamic variables were boosted up in downstream, except flow velocity. The present research highlighted that the steeper gradient of the R. Deo had enhanced its competency to transport medium-sized grains to the R. Manu, where fine grains were commonly found. Moreover, increased wetted perimeter in downstream specified more friction between channel bed and its flow consequent upon reduced flow velocity with extra sediment load accumulation.

9 citations

Journal ArticleDOI
TL;DR: In this article, the authors compared the scour pattern upstream of square and circular orifices with equal opening areas of 38.45 cm2 and found that the influence zone area upstream of the square orifice is 1.46 times larger than the circular orifice.
Abstract: Scour pattern upstream of square and circular orifices with equal opening areas of 38.45 cm2 are compared experimentally. A total of 16 tests for four constant heads, two initial conditions of fixed bed versus mobile bed and two non-cohesive sediments used as the bed layer are performed. The bed profile is surveyed by an acoustic bed profiler and the velocity distribution is measured using an ADV instrument. In the fixed-bed tests the thickness of sediment layer below the orifices’ invert is 2 mm and the observations show that the influence zone, which is the zone exposed to excess shear stress in which particles are removed, is elliptically shaped in both orifices with larger ellipse radius in transverse direction. The influence zone area upstream of square orifice is 1.46 times larger than the circular orifice. Observations of the mobile-bed tests indicate that the geometrical scour parameters, namely maximum depth of scour, length and width of the scour hole increase with the head of water upstream of both orifices. It is also found that the maximum scour depth upstream of square orifice is approximately two times deeper than that of circular orifice. Meanwhile, scour length and width, upstream of square orifice are, respectively, 10–15 and 20–33% larger than those of circular orifice. Finally, the measurements of the longitudinal velocity profiles along the centrelines of the orifices for both orifices are performed. The results indicate the existence of three separate zones of velocity distribution upstream of the orifices.

8 citations

Journal ArticleDOI
TL;DR: In this paper, experiments were conducted to control sediment entry into an intake channel using submerged vanes in a physical model with a rectangular mobile-bed main channel and a trapezoidal rigid-bed intake channel diverting at an angle of 45°.
Abstract: Intake canals are used to withdraw water from rivers for various purposes. Sedimentation in the intake canal reduces the quality and quantity of water being delivered. In this study, experiments were conducted to control sediment entry into an intake channel using submerged vanes in a physical model with a rectangular mobile-bed main channel and a trapezoidal rigid-bed intake channel diverting at an angle of 45°. The variables in the study included vane angle, number of vane rows, and vane spacing in terms of mean flow depth in the main channel. In addition to the commonly used vane array with uniform vane heights, three other vane-height configurations were also tested. The least local scour around vanes and highest sediment reduction (~70%) were observed for vanes oriented at a 15° vane angle with an increasing vane-height configuration placed in two rows. It was also observed that control of sediment entry into the intake canal increased with an increase of both vane spacing and number of vane rows.

7 citations

Journal ArticleDOI
14 Jun 2018
TL;DR: A confluence is a place where two flows with different flow and sediment characteristics merge together as discussed by the authors, which is a common occurrence along the natural rivers as well as artificial open channels.
Abstract: A confluence is a place where two flows with different flow and sediment characteristics merge together. Confluences are common occurrences along the natural rivers as well as artificial open channels. In general, a lateral flow confluences into a main flow at various angles. The confluence angle influences the flow and sediment transport at the confluence region. The bed erosion occurs because of turbulence at the confluence. Sometimes, the bank opposite to the direction of lateral flow fails due to the increase in lateral momentum. In addition, the main flow width in the downstream of the confluence increases due to increase of discharge. A confluence is characterized by the presence of a stagnation zone, a separation zone, a mixing layer and the recovered flow in the downstream. A secondary circulation (helicoidal flow cells) induced by the centrifugal action of the lateral flow when merging with the main flow leads to formation of a scour-hole along the central portion of the confluence. The eroded soil from the confluence poses problems by deposition in the downstream locations such as check dams, barrages and reservoirs resulting in reduction of water storage capacity as well as water quality. Hence, this necessitates studies on control of bed erosion at the confluence.

6 citations