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Sutro Weir Research

Introduction

Definition of Weir : A type of small overflow dam that can be used for flow measurement. The Linear Flow Orifice Meter is a mimic of this weir.
Definition of Sutro Weir : The discharge (flow) through the weir is proportional to the head (water depth above a reference plane located at one third of the depths of the crest of the base weir).
Development : The linear-proportional weir was developed by Stout in 1897 and was theoretically based, the design stipulated the width at the base as infinite. In 1908 Sutro modified the design to create a practical linear-proportional weir. The weir has a rectangular base and the flow through the weir is proportional to the height of the water through the curved portion of the weir plus

of the height of the rectangular base ie.

Equations Page Here

Source 1: Prof. B.S. Thandaveswara from the Indian Institute of Technology Madras website


Figure 1: Sutro weir with constraining equations.

  • Note: The rectangular base is present in the design merely to simplify evaluation and analysis. Flow proportional to water height begins above the rectangular weir.
Variables

W = base of rectangular weir
s = height of rectangular weir
h = weir height above rectangular weir
c = constant of proportionality

= coefficient of discharge, ranges from 0.0597 to 0.619

= Flow through rectangular weir

= Flow through upper portion of weir,Important Parameter
Q = Total Discharge

= vena contracta area ratio, average value is 0.62
g = acceleration due to gravity

Source 2: Practical Constant-Accuracy Linear Weir K. Keshava Murthy and M. N. Shesha Prakash, Journal Irrigation and Drainage Engineering 120, 550 (1994)

  • the text is available here, and access to the text is available at the following link
    Summary:

The paper explores a different weir design that also results a discharge that is proportional to the depths of head. The design has two parts, one is the outside edge of part of a circle and the rest of the weir is a sloped straight line. The redesign was tested because the changes would make construction easier. The results showed a high level of accuracy, +/- 1% in the head range 0.5R <= h <= 7.9R (R is the radius of sector of circle, the coefficient of discharge was experimentally shown to be 0.619. Figure 1 is a visual representation of the design.

Source 3: Geometrically Simple Logarithmic Weir K. Keshava Murthy, H. S. Ramesh, and M. N. Shesha Prakash, Journal Irrigation and Drainage Engineering 121, 419 (1995)

  • the text is available here, and access to the text is available at the following link

Note sources 2 and 3 were found through the ASCE research library at http://scitation.aip.org/hyo/

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