On the Effect of Block Roughness in Ogee Spillways with Flip Buckets

Mining activities can endanger the stability of hydraulic structures. Numerical modeling of local scouring around hydrodynamic and circular bridge pile groups, due to the action of clear water conditions via non-cohesive sediment, was performed using a computational fluid dynamics (CFD) model, a large eddy simulation (LES) turbulence model, and a van Rijn sedimentary model with FLOW-3D software. The pile groups were positioned upstream and downstream of a sand mining pit. The results showed that the scour depth around the downstream pile group was greater than that of the upstream one. Using hydrodynamic piers reduced the scour depth upstream of all piers and the material harvesting pit. The maximum reduction in scour depth was observed in front of the fifth pier, with a 29% reduction in scour depth. Additionally, for all models, as the material harvesting pit was moved downstream, the downstream turbulence was enhanced and stronger flow reversal and horseshoe vortices were detected in from of the downstream pile group. The flow patterns around the pile group showed that the presence of hydrodynamic piers in the upstream pile group leads to a decrease in the maximum flow velocity, whereas, when such piers were positioned in the downstream pile group, the velocity increases.

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“…It is related to the porous media and the entry of secondary flow into the computational domain. The equations of motion are as follows [27]:…”

Section: Flow Field Simulationmentioning

confidence: 99%

Investigation of Local Scouring around Hydrodynamic and Circular Pile Groups under the Influence of River Material Harvesting Pits

Daneshfaraz

Ghaderi

Sattariyan

et al. 2021

Water

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“…The water flow depths upstream the broad-crested models and downstream the hydraulic jumps were measured using pointer gauges with 1 mm accuracy. The first, upstream, point gauge was located at 3∆Z to 4∆Z upstream of the models [34][35][36][37]. The second point gauge, located downstream of the hydraulic jumps, was used to measure the sequent depths of the hydraulic jumps.…”

Section: Experimental Workmentioning

confidence: 99%

“…The RNG k-ε was proposed by Yakhot and Orszag [41] and represents a modified version of the k-ε standard model. In particular, the RNG k-ε turbulence model has an additional term in its ε equation (see successive Equation ( 14)) that improves the accuracy for quickly strained and swirling flows and also has good accuracy based on the results of numerical investigations by Bayon et al [28], Daneshfaraz et al [35], Ghaderi et al [42], Lauria et al [43], Ghaderi et al [44] and Pourshahbaz et al [45]. The adopted turbulence scheme is a two-equation model that is expressed as:…”

Section: Numerical Modelling Analysismentioning

confidence: 99%

Experimental and Numerical Study of the Effects of Geometric Appendance Elements on Energy Dissipation over Stepped Spillway

Ghaderi

Abbasi

2021

Water

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In the stepped spillway, the steps, by providing an artificial roughening bed, dissipate the flow of energy more than other types of spillways, so the construction costs for stilling basin are reduced. However, what is important in this type of spillway is increasing the effectiveness of steps in the rate of energy dissipation. The present study deals with experimental and numerical simulations regarding the influence of geometric appendance elements on the steps and its impact on the energy dissipation performances, flow patterns properties, turbulent kinetic energy, flow resistance and the Darcy roughness. The localization of inception point of air entrainment is also assessed. To this aim, different configurations are taken into account. The computational procedure is validated with experimental results and then used to test the hydraulic behavior of different geometric configurations. The results showed that the appendance elements on the steps increased the turbulent kinetic energy (TKE) values and Darcy–Weisbach friction and the energy dissipation increased significantly. By reducing the height of the elements, energy dissipation and the TKE value increase more significantly. With the appendance elements on step, the air entrainment inception locations a positioning further upstream than the flat step stepped spillway.

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“…The experimental model includes a simple inclined drop as a control model, an inclined drop equipped with hole and non-hole fishways. A vertical sluice gate downstream of the laboratory flume has also stabilized the hydraulic jump [33]. A general schematic presentation of the flume is provided together with the prototype models in Figure 1.…”

Section: Experimentally Equipmentmentioning

confidence: 99%

Laboratory Investigation of Hydraulic Parameters on Inclined Drop Equipped with Fishway Elements

et al. 2021

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This study aims to provide a way to increase the energy dissipation of flow in the inclined drop with environmental and economic considerations. Eighty-one experiments were performed on three types of simple inclined drop and inclined drop equipped with hole and without hole fishway elements with a 200~600 L/min flow rate. In this study, the effect of using fishway elements on hydraulic parameters regarding flow pattern, energy dissipation, relative downstream depth, relative aeration length, relative length of the hydraulic jump, and downstream Froude number of an inclined drop was investigated through physical modeling following the symmetry law. The results showed that in all experimental models, with increasing the relative critical depth parameter, the energy dissipation values increase, and the downstream Froude number decreases. The parameters of relative downstream depth, relative length of a hydraulic jump, and relative aeration length also increase with increasing relative critical depth. On average, 88% of the flow energy dissipation increases with the design of the fishway elements on the structure compared to the simple drop. Model M7 (with holes fish elements) shows the highest energy dissipation, and Model M2 (without holes fish elements) has the highest flow aeration length and relative downstream water depth.

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On the Effect of Block Roughness in Ogee Spillways with Flip Buckets

Cited by 26 publications

References 38 publications

Investigation of Local Scouring around Hydrodynamic and Circular Pile Groups under the Influence of River Material Harvesting Pits

Investigation of Local Scouring around Hydrodynamic and Circular Pile Groups under the Influence of River Material Harvesting Pits

Experimental and Numerical Study of the Effects of Geometric Appendance Elements on Energy Dissipation over Stepped Spillway

Laboratory Investigation of Hydraulic Parameters on Inclined Drop Equipped with Fishway Elements

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