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The spur dikes are structures that usually used for flow diversion from erodible wall and they usually create a appropriate path for directing the flow, flood control, protection of external walls, and some other
cases. Through modifying the hydraulic conditions and creation of smooth flow, spur dikes can decrease
water erosion force and power of s...
Citations
... The potential near-bank erosion was found to be at a minimum for an angle of 135 according to measured maximum scour volume. Giglou et al. (2018) tested a single spur dike with angles of 45 , 75 , 90 , 105 , and 120 , and reported that by increasing the spur dike angle relative to the flow direction, the length and diameter of the produced vortex grow. The velocity decreased the most when the spur dike model was oriented at 120 . ...
Local scour is a phenomenon leading to the localized lowering of the channel bed due to the imbalance of sediment transport. As spur dikes protrude into the natural channels, local scour could be triggered. Accurate estimation of local scour around spur dikes is crucial for the effectiveness of erosion control and prevention and habitat enhancement measures. In the current study, the correlations between the maximum scour depth and the overtopping ratio, spur dike dimensions, ice cover roughness, and grain size of the bed material is investigated. Under both open channel and ice-covered flow conditions, a variety of experiments were done in a large-scale outdoor flume with different experimental setups. The results revealed that the scour depths around submerged spur dikes increased with increases in the densimetric Froude number and the decreases in the overtopping ratio and alignment angle. The maximum scour depth around a submerged angled vertical wall spur dike is significantly affected by the presence of an ice cover on the water surface, namely, the rougher the cover, the deeper the scour hole. Based on data collected from the laboratory experiments, an existing maximum scour depth estimation equation has been modified to consider the influence of the cover condition and the submergence level. The calculated results showed high accuracy in estimation of the measured data.
... [1][2][3] Thus, it is essential to protect the rivers and channels against erosion and damage caused by the flowing water. [4] The erosion of bed materials, particularly sediment, and soil, caused by the action of flowing water in rivers, streams, or other water bodies refers as scour. [5][6][7] Local scour around the hydraulic structure is a significant problem and affects its safety and also public safety, and the economy. ...
... The upstream side of the spur dike divides the flow, which forms vortices, and local scour occurs at the downstream side [19,20] and it may lead to scour holes in the vicinity of the dikes. [4,21,22] The mechanism of scour around spur dike is similar to abutments, and it is explained by researchers. [23][24][25] The horseshoe and wake vortices are mainly responsible for scour around the vicinity of the spur dike, and with secondary vortices causes complex interactions between the fluid and sediment bed materials. ...
... There are several experimental studies conducted on scour around the spur dikes and other hydraulic structures. [4,15,20,21,26] ...
Spur dikes are popular river training structures used for flow diversion, flood control, bank protection, and improving navigation. This paper aims to study the numerical modeling of scour depth in the vicinity of a rectangular spur dike using the renormalization group (RNG) turbulence model and sedimentary van Rijn model with nested mesh configuration using FLOW-3D. This study is also carried out to analyze the three turbulence models such as RNG, k−ε, and Large-Eddy simulation (LES), for estimating the scour depth and evaluating the temporal variation of maximum scour depth. It is observed that scour depth is overpredicted with the LES model configuration used in the present study, as compared to k−ε and RNG models. Furthermore, the scour depth increases by increasing the bed load coefficient near to the spur dike. Simulated results show a good agreement within a 5% error with experimental results regarding the net change of sediment elevation and scour depth.
... By constructing the spur dike, the flow path contracts, and resultantly the flow velocity near the structure increases which leads to increased average velocity in the contracted section. This is why using spur dikes is a good solution for managing how rivers flow, controlling the movement of water and passage of water under bridges, and preventing the erosion of river banks and edges [1]. ...
... At downstream, the vortex zone formed around one impervious spur dike was investigated using RNG (Re-Normalization Group model) turbulence method by Giglou et. al [1]. When water passed through impervious spur dike, it resulted into vortex zone formed around impervious spur dike of four times the length of spur dike. ...
The present study examines how adjusting vegetation patches in a rectangular open channel with two impermeable spur dikes alters the displacement of the recirculation region. The Reynolds stress turbulence model is implemented via the 3D numerical code FLUENT (ANSYS). Mean stream-wise velocity profiles were drawn at selected positions and at mid of flow depth i.e., 3.5 cm, a horizontal plane is cut through the open channel for analyzing velocity contours and streamline flow. The findings indicate that the stream-wise velocity profiles showed fluctuations in the presence of different shapes and arrangement of cylindrical patch discussed and the maximum velocity within the field of spur dike is of the order of 0.018 m/s due to the prism shape. By changing the position of the cylindrical patch, the location of the recirculation region displaces within the field of impermeable spur dike.
... Additionally, data extraction can be performed only from the locations where gauges and sensors are installed. On the other hand, a wide range of hydrodynamic fluid flows and robust numerical simulation modelling can be performed using CFD and it allows for examination of any location in the region of interest [19,[37][38][39][40][41][42][43]. It can theoretically simulate any physical condition and allow the study of a specific isolated phenomenon. ...
... where ρ is fluid density, t is time, u i is the i-th component of filtered velocities, x j is cartesian coordinates, p is filtered pressure, ν is kinematic viscosity, and τ ij is subgrid-scale (SGS) stress [36,37]. The van Rijn equation, as a sediment transport equation, evaluates the dimensionless rate of bed-load transport [38]. ...
Scouring around the bridge pier is a natural and complex phenomenon that results in bridge failure. Failure of bridges have potential devastation and public safety and economic loss, which lead to political consequences and environmental impacts. Therefore, it is essential to countermeasure the scour around the bridge pier. This paper studies the effects of four different airfoil-shaped collars (i.e., bc1 = 1.5b, bc2 = 2.0b, bc3 = 2.5b and bc4 = 3.0b, where bc and b are the diameter of the airfoil-shaped collar and pier, respectively) as a scour countermeasure. All the experiments are conducted under clear water conditions with uniform sediment and a constant water depth (y) of 10 cm. Airfoil-shaped collar is placed at four elevations, i.e., bed level, y/4, y/2 and 3y/4 above the sediment bed level. It is observed that the maximum percentages of scour reduction of 86, 100 and 100% occurred due to protection provided by the collar bc2, bc3 and bc4, respectively, at sediment bed level. So, collars bc2, bc3 and bc4 are efficient at the sediment bed level. The profiles of scour hole show that the length of the transverse scour hole is greater than that of the longitudinal one. Numerical investigation of the morphological changes in sediment bed and scour depth contours is developed using the FLOW-3D for the pier with and without the airfoil-shaped collar.
... KIIs indicated that lack of researches to investigate the main problem and new results like improved plant seed suitable for respective agro-ecology and soil type, grass and to identify the new knowledge how to practice WSM activities. In relation to this, Walie, [9] indicated that lack of technology is the major threats of SWC practices in the means of difficulty to tillage, need much labor, need incentive to implement and reduce farm size. ...
Natural resources have been degrading due to intensive agricultural activities in many developing countries. To rehabilitate the degraded natural resources watershed management practices has become the key approach to minimize loss of such resources. The study examined the contraints of watershed management practices on smallholder farmers' livelihood in Hidabu Abote Woreda, North Shewa, Oromia regional State, Ethiopia. The study employed a mixture of qualitative and quantitative methods. Data was generated through household (HH) survey, key informant interview and focuses group discussion. The quantitative data were generated from 266 household, where the sample sized detrained by standard method. Tables and narrative method, was used to examine the contraints of Watershed Management practices of smallholder farmers. The study results revealed different factors constrained the Watershed Management practice that include lack of training and low quality of trainings given either for extension or farmers, lack of appropriate technology, open grazing, deforestation, limited maintenance of SWC structures, inadequate extension services, insufficient (small) farmland holding, shortage of cash income to cover agricultural input costs, poor (traditional) agricultural practices, fearing reduction of farmland size due to land closure for conservation. The policy makers and actors emphasize on the solving the limitation through providing technical or action oriented training and awareness creation through considering indegineus knowledge, allocation of extension service and provide materials (tools) used Soil Water Conservation are the key reccomondation finded.
... To counteract the undesired reservoir sedimentation, necessary measures are required. River training approaches are commonly used, which include construction of spur dikes [28][29][30], rock vanes, and bendway weirs [31,32], various types of revetments [33], and dredging [34]. Each approach has its advantages and limitations. ...
At the multigate sluice structure on a fluvial river, undesired sediment deposition affects the normal operation of the reservoir in question. Physical and numerical models are hybridized to help explore flow and sedimentation patterns. Field and laboratory investigations show that the deposition is attributable to the formation of large recirculation zones at low and medium discharges. As a potential countermeasure, an array of guide vanes is recommended to cope with the concern. Their attack angle with the flow is a dominant parameter that needs to be evaluated. Tests in the fixed-bed model demonstrate that the vanes bend the reservoir flow towards the sluice and suppress the circulation zones along both banks. The favorable range of attack angle is 15°‒20°. With the examination of sedimentation of both bed and suspended loads, the numerical modeling indicates that the sediment-removal efficiency increases with an increase in attack angle. By weighing the flushing efficiency and the risk of local scouring at the vanes, the 15° vane layout is recommended. This study is expected to provide a reference for guide-vane design in similar situations.
... Repelling spur dike is constructed with an inclination in the upstream direction, whereas attracting spur dike is constructed with an inclination in the downstream direction, which reflects the flow far from itself. The deflecting spur dyke is constructed perpendicular to the flow of the river in the transverse direction (Giglou et al. 2018). ...
A spur dike is a hydraulic structure, protruding in a river or channel used for several purposes like protection of river-bank erosion and deepening of the main channel. The present paper discusses pre-existing research work on flow pattern and prediction of temporal and maximum scours depth around the spur dikes placed in different locations at 90∘ and 180° curved channels. The equations having approximately 2.367, 4.47, 0.17, and 0.271 (average) times with their corresponding experimental data. The parameters, influencing the scour process and flow pattern, have been identified as the ratio of flow intensity to critical velocity (V/Vc ≥ 1) is below 1 and special kind of bedding material is approximately 10 % greater than under live-bed condition and many more. The numerical value of the Froude number and the geometry of the bed surface material are also discussed in this paper. Based on these parameters, the empirical formulations and experimental studies on local scours around the straight, L-shaped, T-shaped spurs, placed at 30°, 45°, 60°, 120°, and 180° azimuthal angles have been discussed. Various numerical schemes proposed in almost seventy-five literatures have been summarized. A critical review of numerical and experimental results found in different works related to temporal and maximum scour depth, flow characteristics, and bed topography around the dike shows that the data and accompanying results are insufficient for the design of spurs used as river structures in curved channels. There are needs to carry out extensive experiments, under various flow conditions, to examine the flow behavior and scouring processes around the spurs. Due to complex flow pattern and scouring processes, taking place around the spur, it becomes difficult to understand the real physics behind these phenomenon and therefore, data-driven models are suggested to arrive at more reasonable relationships required to be used for design purposes.
... The recirculation and vortex regions generated directly downstream of repelling and attracting spur dikes [23], a single spur dike (impermeable) at different angles [24], and a succession of spur dikes (permeable) [25] have all been investigated using numerical models in an open channel. Wooden piles [26], debris mounds [27], and wire cages [28] can all be used to reflect the permeable spur dike. ...
... The collapse of spur dike (impermeable) was caused by the scour hole depth. Giglou et al. [24] used RNG turbulent technique to investigate the vortex region created just downstream of impermeable single spur dike at various angles. As the flow approaches the spur dike (impermeable), the vortex area generated is four times the length of spur dike (impermeable), subsequent velocity flow of silt's slowing down, and started deposition. ...
In this study, Computational Fluid Dynamics software (ANSYS Fluent) is used to investigate the turbulence and flow characteristics around spur dike in an open channel. After validating the numerical model with the experimental results, the spur dike was made permeable by providing staggered pores of varying permeabilities (22%, 37%, and 52%). Additionally, the pores angle was also varied (0°, 15°, 30°, and 60°) in order to elucidate the extent of flow diversion from the spur dike field towards the main channel. The flow characteristics around permeable spur dike are compared, including velocity distribution, reattachment length, roughness coefficient (n), turbulence kinetic energy (TKE), turbulence intensity (T.I), and wall shear stress. The results of turbulence and flow characteristics showed an improvement in the use of permeable spur dikes (0°) compared to impermeable spur dikes. The efficiency and controlled range of these results were further enhanced and achieved, while the permeability with increasing pore angles is used. When pore angle of spur dike increased to 60°, the increasing trend of mean streamwise velocity at the downstream (d/s) was reduced up to 25% and at the tip of the spur dike TKE, T.I, and mean streamwise velocity reduction were 22%, 15%, and 4%, respectively. This research recommends that a permeable spur dike with pores angle is ideal for protecting the tip of spur dike, riverbanks, and aquatic habitat during extreme floods. It also reduces reattachment length (br) and roughness coefficient (n).
... They indicate that Froude number is a significant parameter in scour depth around the groyne, and other parameters play secondary role, which was later also confirmed by Rashak and Khassaf [126]. Giglou et al. [131] conducted an analysis of flow pattern around spur dikes by a 3D numerical model, and showed that vortex length behind the spur dike is four times longer than the length of spur dike, and with approximately 1.2 times the spur dike length. Pandey et al. [132] developed two novel methods to estimate maximum scour depth around the spur dike in a uniform sediment condition that consists of three standalone machine-learning approaches. ...
Bridge piers on large rivers are often protected from scouring using launchable stone, such as a riprap sloping structure. While such scour countermeasures are effective for pier protection, they significantly alter flow conditions in the bridge opening by overtopping flow and flow contraction, deflecting the formation of the scour hole downstream and exposing the downstream riverbed to additional scour. This paper provides a comprehensive and relevant review of bridge scour estimation methods for piers with a riprap sloping structure installed as a scour countermeasure. Research on empirical methods for bridge scour estimation is reviewed and analyzed with formulae used for comparable structures—complex pier formulae and formulae for river training structures. A summary of relevant formulae applicable to piers with installed scour countermeasures is provided, as well as a discussion on the possible future research directions that could contribute to the field.
... These constructions have been widely used for many purposes, such as river bank protection, flood control, improvement of a navigational course, control of scour process, landscape improvement, and ecosystem restoration [2]. Regardless of the different types of spur dikes, they redirect flow from the river bank and affect the flow regime, flow velocity, sediment transportation, and consequently scour process [3]. ...
Spur dikes are well-known structures that are widely used in rivers and coastal regions. Depending on their types, sizes, and orientation angles, spur dikes can substantially change flow characteristics. Results of previous studies indicate that the presence of an ice cover in rivers can cause complicated flow structures. The present experimental study investigates velocity fields and turbulence structures in the vicinity of spur dikes under ice cover with different roughness coefficients. The spur dikes were set up at the following three angles of orientation, 90°, 60°, and 45°. Our results show that the strongest velocity fluctuation occurs immediately above the scour hole surface and very close to the dike tip. The increase in the dike angle toward upstream, the velocity component values increase, leads to a larger scour hole. Results show that an increase in dike angle of each 10° (from 45° to 90°) increases the scour depth between 5% and 10%, depending on flow conditions. Furthermore, the increase in the cover roughness coefficient and the blockage ratio of a spur dike leads to a further increase in turbulence kinetic energy and 3D velocity components values. The findings of this study imply that the appearance of an ice cover can increase turbulence intensities up to nearly 30%.
