scholarly journals A Study on Flood Discharge Capacity and Hydraulic Characteristic of Labyrinth Weir as a Side-Channel Spillway

2008 ◽  
Vol 41 (1) ◽  
pp. 65-74 ◽  
Author(s):  
Sae-Hoon Park ◽  
Young-Il Moon
Keyword(s):  
Discharge Capacity ◽  
Hydraulic Characteristic ◽  
Side Channel ◽  
Labyrinth Weir ◽  
Flood Discharge

Performance of rectangular labyrinth weir- an experimental and numerical study

2022 ◽  
Author(s):  
Mosbah Ben Said ◽  
Ahmed Ouamane
Keyword(s):  
Discharge Capacity ◽  
Numerical Study ◽  
Flow Behavior ◽  
Rectangular Channel ◽  
Experimental Models ◽  
Absolute Relative Error ◽  
Labyrinth Weir ◽  
Specific Discharge ◽  
Labyrinth Weirs ◽  
Good Agreement

Abstract Labyrinth weirs are commonly used to increase the capacity of existing spillways and provide more efficient spillways for new dams due to their high specific discharge capacity compared to the linear weir. In the present study, experimental and numerical investigation was conducted to improve the rectangular labyrinth weir performance. In this context, four configurations were tested to evaluate the influence of the entrance shape and alveoli width on its discharge capacity. The experimental models, three models of rectangular labyrinth weir with rounded entrance and one with flat entrance, were tested in rectangular channel conditions for inlet width to outlet width ratios (a/b) equal to 0.67, 1 and 1.5. The results indicate that the rounded entrance increases the weir efficiency by up to 5%. A ratio a/b equal to 1.5 leads to an 8 and 18% increase in the discharge capacity compared to a/b ratio equal to 1 and 0.67, respectively. In addition, a numerical simulation was conducted using the opensource CFD OpenFOAM to analyze and provide more information about the flow behavior over the tested models. A comparison between the experimental and numerical discharge coefficient was performed and good agreement was found (Mean Absolute Relative Error of 4–6%).

Response of flood discharge capacity to the channel boundary and upstream conditions in a braided reach

2020 ◽  
pp. 2188-2195
Author(s):  
Yifei Cheng ◽  
Junqiang Xia* ◽  
Shanshan Deng ◽  
Meirong Zhou
Keyword(s):  
Discharge Capacity ◽  
Flood Discharge ◽  
Channel Boundary ◽  
Braided Reach

scholarly journals Evaluation of Dimensions and Drainage Performance Office in the Aceh Tamiang Area Kuala Simpang

2021 ◽  
Vol 3 (1) ◽  
pp. 20-32
Author(s):  
Kamaluddin Lubis
Keyword(s):  
Channel Capacity ◽  
Discharge Capacity ◽  
Return Period ◽  
Rainfall Intensity ◽  
Drainage Channel ◽  
Flood Discharge ◽  
Discharge Plan ◽  
Runoff Discharge ◽  
High Degree

The Aceh Tamiang office area is one of the office areas in Kuala Simpang which consists of various offices in the Aceh Tamiang area. The purpose of this research is to identify the drainage condition of the existing primary drainage channel which accommodates runoff discharge, the shape and direction of the flow in the inundation channel in the Aceh Tamiang Kuala Simpang office area, which is expected to help solve the problem of flooding in the 832 m3 / second. And for the channel capacity in this primary drainage drainage of 0.829 m3 / sec, the value is smaller than the planned flood discharge (Qr). Rainfall intensity (I) of 126,432 mm / hour. The plan flood discharge (Qr) for a 5-year return period yields 2,551 m3 / second and the value for channel discharge capacity (Qs) is obtained from the calculation of 2,216 m3 / second. This value is smaller than the value of the planned flood discharge.area. From the results of research conducted by the Aceh Tamiang Kuala Simpang office area is a location with a fairly high degree of rainfall, with a rainfall intensity (I) of 126,432 mm / hour and a flood discharge plan for a 5-year return period obtained a result of 0.

scholarly journals Effect of Tail Regulators on Euphrates River Flood Capacity at Al Nassiriyah City

2019 ◽  
Vol 26 (1) ◽  
pp. 43-54
Author(s):  
Atheer Ghazi Shayea ◽  
Hayder A. Al Thamiry
Keyword(s):  
Discharge Capacity ◽  
Return Period ◽  
River System ◽  
Hydraulic Structures ◽  
Euphrates River ◽  
Flood Discharge ◽  
Maximum Discharge ◽  
River Flood ◽  
River Training ◽  
The Impact

Euphrates River extends about 125 km within the study area located in Annassiriyah City, Dhi Qar Governorate, Iraq. The impact of the seven hydraulic structures on the discharge capacity of the Euphrates River needs to be considered. The main objectives of this research are to increase the discharge capacity of Euphrates River within Annassiriyah City during flood seasons and study the impact of these hydraulic structures on the river capacity by using HEC-RAS 5.0.3 software. Five scenarios were simulated to study the different current condition of Euphrates River within Annassiriyah City. Other additional four scenarios were implemented through river training to increase the river capacity to 1300 m³/s; it is the flood of 100 year return period. The results of the current condition showed that the maximum discharge capacity of Euphrates River within Annassiriyah City is just 300 m³/s. The results of applied improvements show that the capacity can reach 1300 m³/s when Al Chibayish Weir was hypothetically removed from the river system. Additionally, the river capacity will be reduced to 600 m³/s when Al Chibayish Weir is considered. It was concluded that the 100-year flood discharge cannot be achieved without removing Al Chibayish Weir from the river system.

scholarly journals Effect of Corner Shape on Hydraulic Performance of One-Cycle Rectangular Labyrinth Weirs

Fluids ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 117
Author(s):  
Omed S. Q. Yousif ◽  
Moses Karakouzian
Keyword(s):  
Discharge Capacity ◽  
Hydraulic Performance ◽  
Acute Angle ◽  
Effective Length ◽  
Hydraulic Efficiency ◽  
Labyrinth Weir ◽  
Rounded Corner ◽  
Side Walls ◽  
The One ◽  
Labyrinth Weirs

The hydraulic performance of rectangular labyrinth weirs has been investigated by many researchers, however, the effects of the corner shape on the hydraulic performance of rectangular labyrinth weirs have not been addressed in the current literature. Accordingly, this experimental study aims to explore the effect of the corner shape of on discharge efficiency of rectangular labyrinth weirs. Five flat-crested rectangular labyrinth weirs, with five different corner shapes, were made of High-Density Polyethylene Plastic (HDPE) and tested in a rectangular flume. Under different overflow discharges, the discharge coefficients for the rectangular labyrinth weirs were determined. The results showed that the shape of corners for rectangular labyrinth weirs was an effective factor. For example, rounding or beveling the corners can significantly increase the discharge capacity of the rectangular labyrinth weirs. However, the rounded corner shape was slightly better than the beveled corner shape. Among all labyrinth weir models tested in this study, the rectangular labyrinth weir with a semi-circular apex showed the highest hydraulic efficiency, while the one with an acute-angle corner shape showed the lowest hydraulic efficiency. For the rectangular labyrinth weir having a semi-circular shape, although the original effective length reduced by about 14%, the discharge coefficient, CL, increased by 16.7% on average. For the rectangular labyrinth weir that has an acute-angle corner shape, although the effective length (LC) of the weir increased by 23%, its discharge capacity decreased by 35.2% on average. Accordingly, improper folding of the side-walls of the rectangular labyrinth weir led to a significant reduction in the weir’s hydraulic performance.

scholarly journals Discharge capacity evaluation and hydraulic design of a piano key weir

2018 ◽  
Vol 19 (3) ◽  
pp. 871-878 ◽  
Author(s):  
Xinlei Guo ◽  
Zhiping Liu ◽  
Tao Wang ◽  
Hui Fu ◽  
Jiazhen Li ◽  
...  
Keyword(s):  
Discharge Capacity ◽  
Complex Geometry ◽  
Unit Discharge ◽  
Labyrinth Weir ◽  
Capacity Evaluation ◽  
Hydraulic Design ◽  
New Type ◽  
Multiparameter Optimization ◽  
Piano Key Weir ◽  
New Formula

Abstract A piano key weir (PKW) is a new type of labyrinth weir that increases the unit discharge at the unregulated spillway inlet of the weir. It is considered to be an important structure in water supply and drainage systems. However, its complex geometry makes it difficult to achieve an optimal hydraulic design, and only a few design equations and criteria are available. This study investigates the discharge capacity of a PKW and evaluates the characteristics of its discharge using various sources of experimental data from a database. First, previously proposed discharge capacity formulas are summarized and analyzed. Then, a new formula that integrates the existing test data with the results of dimensional analysis and multiparameter optimization is proposed. The weir characteristics are evaluated using the proposed formula and a mathematical model. The results show that both the proposed formula and numerical model are promising approaches to evaluate the discharge capacity of an A-type PKW and can guide its design.

scholarly journals Current and Modified Flood Discharge Capacity of a Reach of Tigris River between Kut and Amarah Barrages

2020 ◽  
Vol 26 (2) ◽  
pp. 129-143
Author(s):  
Maysam S Abbas ◽  
Riyadh Z. Azzubaidi
Keyword(s):  
Cross Section ◽  
Discharge Capacity ◽  
Cross Sections ◽  
Flood Plain ◽  
Main Channel ◽  
Water Levels ◽  
Flood Wave ◽  
Tigris River ◽  
Flood Discharge ◽  
Lateral Inflow

This study was conducted to examine the discharge capacity of the reach of the Tigris River between Kut and Amarah Barrages of 250km in length. The examination includes simulation the current capacity of the reach by using HEC-RAS model. 247cross sections surveyed in 2012 were used in the simulation. The model was calibrated using observed discharges of 533, 800, 1025 and 3000m3/s discharged at Kut Barrage during 2013, 1995, 1995 and 1988, respectively, and its related water level at three gauge stations located along the reach. The result of calibration process indicated that the lowest Root Mean Square Error of 0.095 can be obtained when using Manning’s n coefficient of 0.026, 0.03 for the Kut- Ali Al Garbi and Ali Al Garbi- Amarah reaches respectively, and 0.03 for the flood plain of the whole reach under study. The reach under study has two lateral inflow streams, UmAljury, which joins Tigris River at station 51km, and Aljabab, which joins Tigris River at station 57km. The discharge of Aljabab varies between 0 and 400m3/s and the discharge of UmAljury varies between 0 and 50m3/s.                     The results showed that the current capacity of the main channel of the reach of the Tigris River between Kut and Amarah Barrages is 400m3/s. The water levels kept less 1m than both levees in case of discharging 1800m3/s from Kut Barrage, with no lateral inflows, and 1700m3/s with lateral inflow. The reach of Tigris River fails to accommodate the flood discharge of 3300m3/s which is the discharge of the flood of 1988 measured at Kut Barage. It can be concluded that the reach had large amount of sediment for the period from 1988 to 2012 and the reach capacity reduced to about half its capacity of 1988 during this period.                                                          The results of removing 12 islands and 2 sidebars by reshaping the current condition into trapezoidal cross-section will decrease the surface water levels by 20cm and flow of 1900m3/s can be discharged safely at Kut Barrage without any lateral inflow and 1800m3/s with lateral inflow from the tributaries. While, expand 58 narrow cross-sections that choking the flow, the water levels along the reach are lowered by an average of 20cm in addition to that 20cm when modifying the cross-sections at the islands and sidebars. In this case, flow of 2100m3/s can safely be discharged from Kut Barrage without any lateral inflow and 1900m3/s with lateral inflow. The result when modifying additional 111 cross-sections showed that the reach can safely accommodate a flood wave of 3300m3/s from Kut Barrage without any lateral inflow and 3000m3/s with lateral inflow.                                                                                                            

Study on Flood Discharge and Countermeasures of ShiQiao Reservoir Spillway

2012 ◽  
Vol 212-213 ◽  
pp. 699-704
Author(s):  
Xiao Qing Wang ◽  
Chang Wu Liu ◽  
Jing Hao Zeng
Keyword(s):  
Discharge Capacity ◽  
Flood Control ◽  
Engineering Geology ◽  
Agricultural Water ◽  
Safe Operation ◽  
Flood Discharge ◽  
The 1950S

The ShiQiao Reservoir was built in the 1950s, whose main functions are irrigation and flood control. With the increasing number of downstream agricultural water, the contradiction is increasingly prominent between pettier beneficial capacity and the raising downstream agricultural water; at the same time, due to the disrepair of spillway and the increase of upstream inflow, the original spillway flood discharge capacity cannot meet the requirements for flood control. On the basis of systematical investigations of engineering geology and hydrogeological, an effective method is proposed for plain reservoirs to solve these problems. The method is, by improving the weir crest elevation and widening spillway to address the inadequate of beneficial capacity and the low standard of flood control spillway. Through the validation of analysis and calculation, this method is feasible and economical. It fundamentally solves the problems of ShiQiao Reservoir, and ensures the safe operation of this reservoir.

scholarly journals Analysis of various parameters affecting weir design and fabrication of Weirs: An Overview

2018 ◽  
Vol 144 ◽  
pp. 01006
Author(s):  
B. Rao Vanishree ◽  
R. Manjula
Keyword(s):  
South Africa ◽  
Structural Stability ◽  
Discharge Capacity ◽  
Geometric Parameters ◽  
Space Requirement ◽  
Labyrinth Weir ◽  
Footprint Area ◽  
Discharge Efficiency

Several geometric parameters influence weir discharge and it is explained in our present study. The PK weir is more efficient than rectangular labyrinth weir due to reduction in entrance losses of PK weir inlet key geometry. PK weir is a type of labyrinth weir with variation in angle. Therefore, in this paper we also discuss about labyrinth weir. PKW are compatible for constructing on existing or new spillway with lesser space requirement and structural stability. PKW are installed in order to increase the discharge capacity for a given footprint area. PKW is used to increase the overflow capacity of existing dams such as, Hazelmare dam (South Africa), Dartmouth dam (Australia). Trapezoidal piano key weirs have higher discharge efficiency than rectangular weirs and it is due to interference wedge. Cd of TPKW is influenced by L/W but Wi/Wo has least effect.

Sign in / Sign up

Export Citation Format

Share Document