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Journal ArticleDOI

Performance and Design of Labyrinth Weirs

01 Nov 1970-Journal of Hydraulic Engineering (American Society of Civil Engineers)-Vol. 96, Iss: 11, pp 2337-2357
TL;DR: In this paper, the authors describe the results of a program of research on labyrinth weirs that is aimed to provide comprehensive performance and design data, and a mathematical model was constructed and a computer program developed which will predict performance to ± 4% accuracy or better over a wide range of operating conditions.
Abstract: The purpose of the labyrinth weir is to increase the discharge per unit width of channel beyond that usually obtained from a conventional weir under identical head conditions. This is achieved by compressing a large length of crest in concertina form into the space available on site. An increase of discharge ranging up to sixfold or more can be obtained. Described are the results of a program of research on labyrinth weirs that is aimed to provide comprehensive performance and design data. The experimental work covered the effects of all primary parameters affecting performance such as crest length magnification, plan geometry, number of cycles, etc. Parallel with the experimental work a mathematical model was constructed and a computer program developed which will predict performance to ± 4% accuracy or better over a wide range of operating conditions. Finally a simple design method is instilled from the experimental and theoretical results.
Citations
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Journal ArticleDOI
TL;DR: In this paper, the capacity of a labyrinth spillway is a function of the total head, the effective crest length, and the crest coefficient, which depends on the angle of the side legs and the number of cycles.
Abstract: The capacity of a labyrinth spillway is a function of the total head, the effective crest length, and the crest coefficient. The crest coefficient depends on the total head, weir height, thickness, crest shape, apex configuration, and the angle of the side legs. Data and a procedure are presented for designing labyrinth weirs for angles between 6° and 35°, and for a range of heads. The design procedure allows the angle of the side legs and the number of cycles to be varied until the desired layout and capacity are achieved. The solution is presented in a spreadsheet format that automatically calculates the dimensions for the labyrinth. Even though the design procedure is quite accurate, it is recommended that the capacity and performance be verified with a model study. The model can evaluate factors not included in the design procedure, like aeration effects at low heads, unusual flow conditions in the approach channel, and flow conditions in the discharge channel.

193 citations

Book
01 Aug 2002
TL;DR: A comprehensive handbook on the hydraulic design of labyrinth spillways from theory to current practice is presented in this paper, which provides a fundamental understanding of the theory of labyrinth weirs and continues with detailed sections on significant factors that affect the discharge characteristics, such as crest shape, weir height, and sidewall angle.
Abstract: This comprehensive handbook on the hydraulic design of labyrinth spillways—from theory to current practice—presents a state-of-the-art method for the effective design of labyrinth weirs. The book provides a fundamental understanding of the theory of labyrinth weirs and continues with detailed sections on significant factors that affect the discharge characteristics of labyrinth weirs, such as crest shape, weir height, and sidewall angle. The most common design curves are discussed, and from these a recommendation is developed for only one design curve to be used in future designs. But because site conditions often vary so much from ideal conditions described in this book, a section on site-specific modeling criteria is included for making accurate predictions of prototype performance. In its review of past studies, the book closely examines many long-held concepts, especially concerning the idea of interference, nappe oscillation, and the definition of which head to use in design computations, and revises them in an effort to advance current thinking based on the latest research.

117 citations

Journal ArticleDOI
TL;DR: In this paper, a method for the hydraulic design and analysis of labyrinth weirs based upon the experimental results of physical modeling is presented for discharge coefficient data for labyrinth weir with quarter-round and half-round crest shapes.
Abstract: A method is presented for the hydraulic design and analysis of labyrinth weirs based upon the experimental results of physical modeling. Discharge coefficient data for labyrinth weirs with quarter-round and half-round crest shapes are presented for sidewall angles ranging from 6 to 35°. Cycle efficiency is also introduced as a design aid, which compares the hydraulic performance of different cycle geometries. Geometric parameters that affect flow performance are discussed. The predictive accuracy of the design method is evaluated through comparisons to previously published labyrinth weir head-discharge data. The companion paper examines nappe behaviors that affect flow performance and presents hydraulic design considerations specific to nappe characteristics.

93 citations


Cites background from "Performance and Design of Labyrinth..."

  • ...Hay and Taylor (1970) presented parameter guidelines, based upon research by Taylor (1968), for sharp-crested triangular and trapezoidal labyrinth weirs....

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Journal ArticleDOI
TL;DR: In this paper, the aeration properties of a triangular plan labyrinth weir were investigated and it was shown that the aerated efficiency of these weirs generally is better than their equivalent-length linear weir and this advantage becomes more pronounced as the weir included angle becomes smaller and also at lower overfall drop heights and higher discharges.
Abstract: A high level of dissolved oxygen is vital for the maintenance of healthy streams and rivers. Structures in rivers can increase dissolved oxygen levels by creating turbulent conditions where small air bubbles are carried into the bulk of the flow. Plunging overfall jets from weirs are a particular instance of this, and the aeration properties of such structures have been studied widely in the laboratory and field over a number of years. On the other hand, labyrinth weirs, where the weir sill is cranked in planform thus increasing their length, have received little or no attention in this context. They have a proven hydraulic advantage over straight weirs of increased discharge at the same head for design conditions. However, they also serve to modify the combined overfall jet as individual jets from adjacent sections of the weir collide. This paper describes an experimental investigation into the nature of these jets and how they affect the aeration performance of a triangular plan labyrinth weir. It is demonstrated that the aeration efficiency of these labyrinth weirs generally is better than their equivalent-length linear weir and that this advantage becomes more pronounced as the weir included angle becomes smaller and also at lower overfall drop heights and higher discharges. These results point to the possible advantage of these type of weir in situations where both hydraulic and aeration performance needs to be optimized.

92 citations

Journal ArticleDOI
TL;DR: In this article, the results obtained from both methods are in a good agreement, and the discharges performances obtained from CFD analyses were compared with the observed results for various Froude number, dimensionless nappe height and weir width.

88 citations