scholarly journals LABORATORY STUDY ON COMPARISON OF THE SCOUR DEPTH AND SCOUR LENGTH OF GROUNDSILL WITH THE OPENING AND WITHOUT THE OPENING

2016 ◽  
Vol 2 (1) ◽  
pp. 151 ◽  
Author(s):  
Ani Hairani ◽  
Djoko Legono
Keyword(s):  
Laboratory Experiments ◽  
Open Channel ◽  
Control Structure ◽  
Negative Impact ◽  
Scour Depth ◽  
Sediment Retention ◽  
Wing Section ◽  
River Bed ◽  
Longitudinal Slope ◽  
Environmentally Sound

River bed control structure what so called groundsill or bottom sill is built for controlling a river bed to remain stable against degradation. Unlike other river obstacles, the presence of groundsill might cause sediment retention upstream of the structure; hence it reduces the supply of sediment to the downstream part of the river. At some extent, the above situation might create unexpected negative impact, not only cease the sediment migration but also disable fish migration, as well as the utilization of river for navigation. This paper presents the hydraulic investigation on various models of groundsill, i.e. groundsill without the opening and groundsill with a certain type of the opening. Series of laboratory experiments were conducted on an open channel flow of 0.75m width and longitudinal slope of 0.05%. There were two types of groundsill, i.e. groundsill without the opening with 0.75m width and 0.05m height, and groundsill with the opening of 0.39m width and 0.005m height of crest at the opening and 0.05m at the wings. Various flow rates were then introduced, necessary data were taken, and the hydraulic phenomena were studied. The results showed that groundsill without the opening produced non-dimensional (relative to the channel width) scour depth of 0.036, and scour length of 0.253. Groundsill with the opening produced scour depth of 0.013 and 0.024 near the downstream end of the wing section and the opening respectively. The scour length of the groundsill with the opening is 0.080 and 0.293 near the downstream end of the wing section and the opening section respectively. Moreover, it can be noted that the presence of the scour depth and scour length of the groundsill with the opening was generally much smaller rather than that of groundsill without the opening. The above results give the evidence that groundsill with the opening is much friendlier and also more suitable for the environment needs.Keywords: control structure, environmentally sound, groundsill, hydraulic phenomenon

scholarly journals Case Study: Model Test on the Effects of Grade Control Datum Drop on the Upstream Bed Morphology in Shiting River

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1898 ◽  
Author(s):  
Ma ◽  
Wang ◽  
Nie ◽  
Yang ◽  
Liu
Keyword(s):  
Model Test ◽  
Control Structure ◽  
Scour Depth ◽  
Highway Bridge ◽  
Scaled Model ◽  
Bed Morphology ◽  
River Bed ◽  
Grade Control ◽  
Erosion Area ◽  
River Reach

This paper conducted an undistorted scaled model test (geometric scale λL = 1:80; the others are derived scales based on Froude similitude) of a 1.3 km-long river reach in Shiting River, China, investigating the impacts of the grade control datum (GCD, defined as the crest elevation of the grade control structure) drop on the upstream bed morphology. Three GCDs and six flood events (occurrence probability 1–50%, discharge = 600–4039 m3/s) were tested on the model. Experimental results indicate that, for a constant GCD, the increase in discharge deepens and widens the upstream river bed. For a lower GCD, the increase in channel depth and width caused by the increasing discharge is greater. For each discharge, the decrease in GCD induces a lower and steeper upstream river bed, widening the upstream main channel. For lower discharge, the GCD drop induces a head cut erosion area upstream of the grade control structure and the head cut erosion area is filled by the upstream sediment when the flow discharge is high. Experimental data also indicate that the maximum general scour depth at the 105th Provincial Highway Bridge is approximately independent of discharge for a constant GCD. For a lower GCD, the general scour depth at the 105th Provincial Highway Bridge increases slightly with discharge.

scholarly journals ANALYSIS OF TSUNAMI SCOUR AROUND SQUARE STRUCTURES USING A PUMP-DRIVEN FLOW METHOD

2020 ◽  
pp. 8
Author(s):  
Rafael Aranguiz ◽  
Oscar Link ◽  
Jose Aliaga ◽  
Oscar Briones ◽  
Ruben Alarcon ◽  
...  
Keyword(s):  
Solitary Waves ◽  
Laboratory Experiments ◽  
Maximum Flow ◽  
Sediment Deposition ◽  
Scour Depth ◽  
Flow Depth ◽  
Field Surveys ◽  
Flow Method ◽  
Tsunami Scour ◽  
Tsunami Event

Estimation of the maximum scour depth is important for defining the size and depth of building foundations in order to avoid failure during a tsunami event (Jayaratne, et al 2016). Traditionally, tsunami scour has been studied in laboratory experiments that use solitary waves. However, it has been demonstrated that this type of wave does not represent well a real tsunami (Madsen et al, 2008). In addition, results from field surveys are based on the scour depth after the tsunami event, studying only the maximum flow depth, and ignoring other hydrodynamic features such as velocity and wave period, as well as sediment deposition. The main objective of this research is to estimate maximum tsunami scour around rectangular structures as a function of realistic tsunami variables.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/ykb-JyL7lsE

scholarly journals Geopolitical Aspects of Channel Processes

2011 ◽  
Author(s):  
Keyword(s):  
Negative Impact ◽  
Eastern Region ◽  
Channel Processes ◽  
Republic Of China ◽  
River Bed ◽  
Boundary Position ◽  
State Boundary ◽  
Far Eastern ◽  
Water Work

When using the Far-Eastern Region as a study case the paper deals with the issues of political tensions between neighboring states (Russia and People’s Republic of China) caused by coinciding of state boundaries with rivers. Main forms of negative impact of channel processes that cause reconsideration (demarcation) of the boundary position have been described. The role of water work facilities that influence the river bed regime transformation and, consequently, fairway/state boundary position alteration is being assessed.

scholarly journals Apron and Cutoff Wall Scour Protection for Piano Key Weirs

Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2332
Author(s):  
Wyatt Lantz ◽  
Brian Mark Crookston ◽  
Michele Palermo
Keyword(s):  
Large Scale ◽  
Open Channel ◽  
Control Structure ◽  
Cutoff Wall ◽  
Specific Design ◽  
Experimental Campaign ◽  
Hydraulic Conditions ◽  
Weir Height ◽  
Scour Protection ◽  
Design Guidance

Piano key (PK) weirs are used in a variety of flow control structure applications, including spillway crests and open channel diversion structures. However, to the best of authors’ knowledge, structure-specific design guidance for scour mitigation is still needed. To fill this gap of knowledge, a systematic experimental campaign was conducted by testing different configurations of horizontal aprons with a cutoff wall. Protection structures were located at the toe of the PK weir. Namely, experiments were performed at large-scale to assess the effect of three apron lengths on downstream scour hole geometry under different hydraulic conditions. It was observed that a horizontal apron deflects the plunging jets originating from the PK weir, thus significantly reducing scour. Experimental evidence allowed corroboration that significant scour depth reduction occurs for an apron length 1.5 times the weir height, with longer aprons found to provide marginal benefits. Finally, also provided herein are tools to estimate the main scour characteristics and help practitioners in optimizing apron design.

UAV Based Multi-Hazard Vulnerability Assessment System for Bridges Exposed to Scour

2020 ◽  
Author(s):  
Okan Özcan ◽  
Orkan Özcan
Keyword(s):  
Load Capacity ◽  
Time History ◽  
Element Model ◽  
Lateral Load ◽  
Assessment System ◽  
Bridge Piers ◽  
Scour Depth ◽  
River Bed ◽  
Principal Axes

<p>Evaluating the multi-hazard performance of river crossing bridges under probable earthquake, flood, and scouring scenarios is a cumbersome task in performance-based engineering. The loss of lateral load capacity at bridge foundations may induce bridges to become highly vulnerable to failure when the effects of scour and floods are combined. Besides, the assessment of local scouring mechanism around bridge piers provides information for decision‐making regarding the pile footing design and for predicting the safety of bridges under critical scoured conditions. Thereby, accurate high-resolution Digital Elevation Models (DEMs) are critical for many hydraulic applications such as erosion, hydraulic modelling, sediment transport, and morphodynamics. In the present study, an automated unmanned aerial vehicle (UAV) based multi-hazard performance assessment system was developed to respond to rapid performance evaluation and performance prediction needs for river crossing reinforced concrete (RC) bridges. The Bogacay Bridge constructed over Bogacay in Antalya, Turkey was selected as the case study. In the developed system, firstly the seasonally acquired UAV measurements were used to obtain the DEMs of the river bed from 2016 to 2019. The transverse cross sections of the river bed that were taken close to the inspected bridge were used to measure the depth of the scoured regions along the bridge piles under the present conditions. Separately, in conjunction with the flood simulation and validation with 2003 flood event (corresponds to Q<sub>50</sub>=1940 m<sup>3</sup>/s), the scour depth after maximum probable flood load according to the return period of 500 years (Q<sub>500</sub>=2560 m<sup>3</sup>/s) were predicted by HEC-RAS software. Afterwards, the 3D finite element model (FEM) of the bridge was constituted automatically with the developed code considering the scoured piles. The flood loads were exerted on the modeled bridge with regard to the HEC-RAS flood inundation map and relevant water depth estimations around the bridge piers. For the seismic evaluation, nonlinear time history analyses (THA) were conducted by using scaled eleven scaled earthquake acceleration records that were acting in both principal axes of the bridge simultaneously by considering maximum direction spectra (SaRotD100) as compatible with the region seismicity. In the analyses; as the scour depth increased, the fundamental periods, shear forces and the bending moments were observed to increase while the pile lateral load capacities diminished. Therefore, the applicability of the proposed system was verified using the case study bridge.</p>

Surface manifestations of turbulent flow

1996 ◽  
Vol 308 ◽  
pp. 15-29 ◽  
Author(s):  
Michael S. Longuet-Higgins
Keyword(s):  
Channel Flow ◽  
Gravity Waves ◽  
Laboratory Experiments ◽  
Open Channel ◽  
Open Channel Flow ◽  
Simple Expression ◽  
Short Waves ◽  
Surface Slopes ◽  
Horizontal Strain ◽  
Steep Waves

The surface of a turbulent, open-channel flow is often characterized by smooth areas of upwelling, each surrounded by a zone of downwelling marked by short steep waves. The dynamics of short waves on such a downwelling region are investigated and some laboratory experiments are proposed. Assuming that the horizontal strain rate Ω is locally constant, a simple expression is derived for the amplitude a of the short capillary–gravity waves, and hence also for the spectrum of the surface slopes.

scholarly journals Estimation of maximum scour depth near a spur dike

2016 ◽  
Vol 43 (3) ◽  
pp. 270-278 ◽  
Author(s):  
Manish Pandey ◽  
Z. Ahmad ◽  
P.K. Sharma
Keyword(s):  
Natural Phenomenon ◽  
Scour Depth ◽  
Flowing Water ◽  
Performance Indices ◽  
Spur Dike ◽  
Bed Erosion ◽  
River Bed ◽  
Spur Dikes ◽  
Dike Failure ◽  
Better Than

Scour is a natural phenomenon in rivers caused by the erosive action of the flowing water on the bed and banks. Spur dikes are constructed across the flow to protect the bank from erosion by shifting of the river away from the bank. The spur dike undermines due to river-bed erosion and scouring, which is generally recognized as the main cause of spur dike failure. In this study, accuracy of existing equations for the computation of maximum scour depth has been checked with available data in the literature and data collected in the present study using graphical and statistical performance indices. Three new relationships are also proposed to estimate the maximum scour depth and maximum scour length upstream and downstream of spur dike. This new relationship for maximum scour depth is shown to perform better than other existing equations.

scholarly journals Вiotechnological approaches to reduce biogenic risks in crop production: potato case

2019 ◽  
Vol 14 (4) ◽  
pp. 403-422
Author(s):  
Svetlana Mikhailovna Lenivko ◽  
Vladimir Ivanovich Boyko
Keyword(s):  
Crop Production ◽  
Negative Impact ◽  
Breeding Strategy ◽  
Genetically Engineered ◽  
Cell Engineering ◽  
Potato Beetle ◽  
Leptinotarsa Decemlineata Say ◽  
Important Approach ◽  
Environmentally Sound ◽  
Introgressive Breeding

The article presents an overview of the biogenic agro-ecological risks in crop production, to reduce which it is possible to use biotechnological approaches. Ways to reduce the negative impact of the two most common harmful objects, the сolorado potato beetle ( Leptinotarsa decemlineata Say) and phytophthoras ( Phytophthora infestans (Mont.) De Bary), which lead to significant losses of potato yield, are considered. It is shown that the currently used methods of plant cell engineering (somatic hybridization and microclonal reproduction) are environmentally sound biotechnological methods of controlling black eye rot potato. The need to develop genetically engineered methods is associated with an exacerbation of biogenic agroecological risks, the reduction of which is an important approach is a proactive introgressive breeding strategy based on cell engineering and molecular methods.

scholarly journals Open Channel Flow over a Permeable River Bed

OALib ◽  
2015 ◽  
Vol 02 (12) ◽  
pp. 1-7 ◽  
Author(s):  
Godwin Christopher Ezike Mbah ◽  
Cyril Ifeany Udogu
Keyword(s):  
Channel Flow ◽  
Open Channel ◽  
Open Channel Flow ◽  
River Bed

Three-dimensional numerical simulation of local scour in the vicinity of circular side-by-side bridge piers with ice cover

2020 ◽  
Author(s):  
Mohammad Reza Namaee ◽  
Jueyi Sui ◽  
Yongsheng Wu ◽  
Natalie Linklater
Keyword(s):  
Laboratory Experiments ◽  
Transport Model ◽  
Numerical Models ◽  
Three Dimensional ◽  
Ice Cover ◽  
Local Scour ◽  
Bridge Piers ◽  
Accurate Estimation ◽  
Scour Depth ◽  
Cold Regions

Local scour around piers is one of the primary causes of collapse of bridges that cross rivers. The most severe scouring occurs in cold regions where ice cover significantly changes the velocity profile. Having an accurate estimation of the maximum scour depth around bridge piers, especially in cold regions, is necessary for a safer design of piers. In this study, 3-D numerical models are compared to laboratory experiments to examine the process of local scour around bridge piers with and without smooth and rough ice cover. By using the equation of Meyer-Peter Müller, the sediment transport model is validated to approximate the transport of the sediment particles. Numerical results showed good agreements with experimental observations where the maximum scour depth and Turbulent Kinetic Energy (TKE) around bridge piers were the highest under rough ice cover conditions.

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