h1. Sutro Weir Research
h2. 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 a weir.
*Definition of Sutro Weir* : The dicharge (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, known as the sutro weir. The sutro wier has a rectangular base and the flow through the wier is proportional to the height of the water through the curved portion of the weir plus {latex} $$ 2\over 3 $$ {latex} of the height of the rectangular base ie. {latex} $$ Q = c [h + {2 \over 3} s] $$ {latex}
h3. [Equations Page Here|LFOM Sutro Weir Equations]
h3. Source 1: Prof. B.S. Thandaveswara from the Indian Institute of Technology Madras [website|http://nptel.iitm.ac.in/courses/Webcourse-contents/IIT-MADRAS/Hydr/pdfs/Unit14/proportional-weir.pdf]
!Sutro Weir Picture.bmp||width=300,height=250!
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.
h5. Variables
W = base of rectangular weir
s = height of rectangular weir
h = wier hight above rectangular weir
c = constant of proportionality
{latex} $$ C_d $$ {latex} = coefficient of dicharge, ranges from 0.0597 to 0.619
{latex} $$ q_w $$ {latex} = Flow through rectangular weir
{latex} $$ q_u $$ {latex} = Flow through upper portion of weir,Important Parameter
Q = Total Discharge
{latex} $$ C_0 $$ {latex} = Proportionality constant, average value is 0.62
g = 9.81
h3. 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|^constant accurqacy linear weir.pdf], and access to the text is available at the following [link|http://dx.doi.org/10.1061/(ASCE)0733-9437(1994)120:3(550)]
h5. 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 wier 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.
!constant-accuracy linear weir.bmp!
h3. 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|^logarithmic weir.pdf], and access to the text is available at the following [link|http://dx.doi.org/10.1061/(ASCE)0733-9437(1995)121:6(419)]
Note sources 2 and 3 were found through the ASCE research library at http://scitation.aip.org/hyo/ |