Maximum discharge in sewer is obtained when the depth of flow is ____ times the full depth
- A0.99
- B0.95Correct
- C0.90
- D0.85
Solution
Concept
Maximum discharge in a circular section
Formula
Qmax at y = 0.95 D (about 0.938 D); Vmax at 0.81 D
Step-by-step solution
1. For a circular sewer running partly full, the discharge is maximum at about 0.95 of the full depth (0.938 D exactly). 2. The velocity is maximum at 0.81 D. 3. Hence 0.95.
Explanation
Discharge exceeds the full-flow value slightly at 0.95 D.
Why the other options are wrong
0.99 is not the point of maximum discharge; 0.90 and 0.85 are lower depths.
Shortcut
Qmax at 0.95 D, Vmax at 0.81 D.
Common mistake
Mixing the depth for Vmax and Qmax.
Correct answer: B) 0.95