What is a sharp crested weir?
Sharp crested weirs (also called thin-plate weirs or notches) are used to obtain discharge in open channels by solely measuring the water head upstream of the weir. Weirs are extensively used in irrigation practices, laboratories and industry.
How do you calculate flow through a weir?
Q = 3.33 B H3/2, where Q is the water flow rate in ft3/sec, B is the length of the weir (and the channel width) in ft, and H is the head over the weir in ft. Use of this equation is subject to the condition that H/P < 0.33 and H/B < 0.33.
How is discharge calculated on a sharp crested weir?
Conclusions: For a suppressed rectangular, sharp-crested weir, equation (8), Q = 3.33BH3/2, may be used if H/P < 0.33 & H/B < 0.33.
Why are sharp-crested weirs used?
Sharp-crested weirs are frequently used for discharge measurements in open channels. They offer a simple, reliable and accurate flow measurement approach if they are properly installed and maintained. Suppressed weirs can be installed in channels with different shapes.
What is the purpose of V-notch and rectangular weir?
To conserve delivery head and reduce head loss, the rectangular and wide V-notch weirs rated by Kindsvater methods should be selected. These weirs provide the capability to use shorter heights from the approach channel invert to the crest.
What is the difference between broad crested weir and sharp-crested weir?
Broad-Crested weirs are much thicker in cross section when compared to sharp-crested weirs. They are commonly used to measure the discharge of larger rivers and agriculture / irrigation canals.
What is Bazin formula?
An equation for calculating the average velocity of water flowing in an open channel, proposed in 1897 by H. E. Bazin (1829–1917). It relates the Chezy discharge coefficient (C) to the hydraulic radius (r) and a channel roughness coefficient (k1) by the formula: C = 157.6/[1 + (k1/r1/2)].
What is the difference between V-notch and rectangular notch?
Head of the V-notch is linear and the rectangular notch is parabolic. A triangular notch gives more accurate results for low discharge than rectangular notch and the same triangular notch can measure a wide range of flow accurately. Actual discharge of V-notch is better than the rectangular notch.