Page 115 - ebook fluid mechanics_finalize

FLUID MECHANICS

5. A venturi meter measures the flow of water in a 75 mm diameter pipe. The difference

between the throat and the entrance of the meter is measured by the U-tube

containing mercury which is being in contact with the water. What should be the

diameter of the throat of the meter in order that the difference in the level of mercury
3
is 250 mm when the quantity of water flowing in the pipe is 620 dm /min? Assume
coefficient of discharge is 0.97.

6. A pitot-static tube placed in the center of a 200 mm pipe line conveying water has one

orifice pointing upstream and the other perpendicular to it. If the pressure difference
between the two orifices is 38 mm of water when the discharge through the pipe is 22

3
dm /s, calculate the meter coefficient. Take the mean velocity in the pipe to be 0.83 of
the central velocity.

7. A sharp-edged orifice, of 50 mm diameter, in the vertical side of a large tank,

discharges under a head of 4.8 m. If Cc = 0.62 and Cv = 0.98, determine;

(a) the diameter of the jet,

(b) the velocity of the jet at the vena contracta.

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