For fluid discharging from a reservoir orifice, the actual velocity at the vena-contracta is given by_____________________?
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Answer: A. Cv . √(2gH)
Explanation
The theoretical Torricelli velocity for fluid discharging from a reservoir orifice is calculated as the square root of two gh. Actual fluid velocity is always lower than theoretical predictions due to viscous boundary friction losses across the orifice rim. Multiplying the theoretical velocity by the velocity coefficient corrects for these frictional reductions to yield actual velocity. The vena contracta represents the specific downstream location where the discharging fluid jet achieves its minimum cross-sectional area. Velocity coefficient is defined strictly as the ratio of actual fluid velocity at vena contracta to theoretical velocity. Orifice discharge characteristics depend heavily on upstream pressure heads, fluid viscosity, and sharp-edged geometric configurations.
Cc times the radical represents the contraction coefficient used for calculating jet cross-sectional area reductions rather than velocity. Cd times the radical incorporates both velocity and contraction coefficients to determine actual volumetric discharge rates. Cv times Va represents an incorrect dimensional product that does not evaluate actual orifice discharge velocity correctly.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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