Answer:
Length of stilling basin = 32.9 feet
Height of end sill = 6.58 feet
Explanation:
Discharge = Q = 400 ft^3 /sec
Slope = 2.5 ft
Width = 20 feet
n = 0.013
we will assume the depth of flow as "d"
Q = 1/n (R)^2/3 (slope)^1/2 A ( here R is the hydraulic Radius)
by substituting the given data in above formula we get:
400 = 1/0.013 * (R)^2/3 * sqrt (2.5/100) * 20d
R = A/P
here, A is the flow area and P is the wetted perimeter
400*0.013 = (20d/(20+20d))^2/3 * sqrt(2.5/100) * 20d
d = 1.42 feet
Depth of stilling channel before the jump will be = d1 = 8 feet
Depth of stilling channel after the jump will be = d2 = 1.42 feet
Length of stilling basin = 5(d2 - d1)
= 5( 8 - 1.42)
Length of stilling basin = 32.9 feet
Now calculating the height of end sill:
Jump height = (8 - 1.42)
Height of end sill = 6.58 feet
