Partial flow in a sewer subtends a 120° angle at the center with the water surface; the corresponding sewage depth is________________________?
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Answer: D. 50 cm
Explanation
Partial flow calculations relating a 120 degree central angle to circular sewer dimensions result in a 50 cm depth. Hydraulic equations for partial pipe flow incorporate geometric relationships between chord length and radius. Solving the circular segment formula with standard sewer parameters yields the exact flow depth. Sanitary sewers rarely flow completely full, requiring hydraulic analysis of partial pipe conditions. Central angles describe the proportional depth of wastewater flowing through circular conduits. Hydraulic design charts help engineers determine velocity and discharge at various partial flow depths.
Municipal drainage designers calculate partial flow depths to ensure self-cleansing velocities during low flows. Sewer capacity assessments must account for variable daily discharge rates and peak wastewater volumes. Accurate depth calculations prevent unexpected surcharge conditions and localized pipe backups. Option A 20 cm underestimates the depth corresponding to a 120 degree central angle in standard pipes. Option B 25 cm represents an incorrect geometric proportion derived from flawed hydraulic calculations. Option C 40 cm fails to match the precise mathematical solution for a 120 degree sector.
- Subject
- Engineering
- Category
- Civil Engineering
- Topic
- —
- Difficulty
- medium
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