An open channel is to be designed to carry 1 m3/s at a slope of 0.006...
For the optimum section
Area = 1 / 2 × 2y × y = y 2
P = 2√2y
y = 0.614 m
View all questions of this test
An open channel is to be designed to carry 1 m3/s at a slope of 0.006...
To find the optimum triangular section depth of an open channel, we can use the Manning's equation. Manning's equation is given by:
Q = (1.486/n) * A * R^(2/3) * S^(1/2)
Where:
Q = flow rate (m^3/s)
n = Manning's roughness coefficient
A = cross-sectional area of the channel (m^2)
R = hydraulic radius (m)
S = slope of the channel
In this case, we are given:
Q = 1 m^3/s
n = 0.011
S = 0.0065
We need to find the optimum triangular section depth, which corresponds to the maximum hydraulic radius. The hydraulic radius is given by:
R = A/P
Where:
P = wetted perimeter of the channel (m)
To find the optimum triangular section depth, we can start by assuming a depth, and then calculate the corresponding values of A, P, and R. We can vary the depth until we find the maximum hydraulic radius.
Let's assume a depth of 1 m and calculate the corresponding values:
For a triangular section, the cross-sectional area is given by:
A = (1/2) * b * y
Where:
b = base width of the triangular section
y = depth of the triangular section
For a triangular section, the wetted perimeter is given by:
P = b + 2 * sqrt((1/4) * b^2 + y^2)
Now, we can substitute these values into the equations and calculate the corresponding values of A, P, and R.
After calculating the values for depth 1 m, we can calculate the hydraulic radius using the formula R = A/P.
Now, we can repeat the above steps for different assumed depths and calculate the corresponding values of A, P, and R. We will find that the maximum hydraulic radius occurs at a depth of 0.614 m.
Therefore, the correct answer is option B: 0.614 m.
To make sure you are not studying endlessly, EduRev has designed Civil Engineering (CE) study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in Civil Engineering (CE).