Question

A 7-ft wide channel carrying water with a flow rate of Q =2 ft/s is metered by a V-notch weir with an included angle of 639 into a second unfinished concrete channel of 1/2 the width of the first, and a depth of 1/2 Y. If the vertex of the notch is 0.2 ft from the ground, please answer the following questiohs: A. What is the upstream velocity of the fluid (uniform approximation away from the weir)? B. What is the downstream velocity (same assumption as above)? C. What is the overfall height H of the weir? D. Is the flow below the weir critical?

Answer 1

Given wrath of channel a flow rate a= 2 ft3/s angle of u-notch 102 o=630 Apply bernoullies cauatan at sections in normal channel and Souq av unfinished concrete channel. tY2 Cassume no lone) y 29 ty, z loui ~ls by, Vi=b2YzU2 by, v izba II 2 z) Uzzun, Q z Ano e or 2= 7xy, xu, z) xl (IA y = 2 150m 2 52.5mp.ee ܚܚ.ܘ - ܢܟ /

B) Uza un auxo.uny M2 21.776 ft lol c) discharge through triangular notch Q = a scd raną szg hila froz630 Cd 20.688 2 = 8 26+0.658 Khan (63) хJ 2x322 xh sh haloob ft y = 2 хучум z zu / 2 = 0.321 m overfall height = hryz 21.06-0.321 20.739 ft . d) critical depth yozi qz azy, u, vi- L' = 0.643 X ouvy 20.285. . Yez 10:28 a 32.2 / ) 200136 ft depth under weir y 2o.2 st yo ye ) flow is subcritical