Flow through Syphon

Q. A syphon is used at point A to draw the water from large reservoir and discharge it to the point B at an atmospheric pressure. If the elevation difference of points A and B is 10 m, what is the velocity (m/s) at point B?

1. 10
2. 14
3. 24
4. 34

Q. In a siphon system employed for carrying water from a reservoir A at a higher elevation to another reservoir B at lower elevation, both being separated by a higher hill, what will be the pressure at the 'Summit'(S)?

1. Equal to the pressure at the water surface of reservoir A
2. Higher than the pressure at the water surface of reservoir A
3. Equal to the pressure at the water surface of reservoir B
4. Less than the pressure at both A and B above

Q. Consider the following statements which are related to the phenomenon of cavitation in fluid flow:

1. Cavitation occurs when local velocity is decreased so that local pressure increases to a high degree.
2. Cavitation occurs if elevation is high thereby decreasing ambient pressure.
3. Cavitation occurs if local velocity is increased so that the local pressure decreases.
4. Cavitation is dependent on vapour pressure of the fluid.

Which of these statements are correct?

1. 1, 2 and 3
2. 1, 2 and 4
3. 1, 3 and 4
4. 2, 3 and 4

Q. Consider the following statements:
Cavitation generally results from a combination of several influences

1. by reduction of pressure intensity below a limiting value
2. by increase in either elevation or the velocity of flow
3. by reduction of pressure load in the system
4. by decrease in the velocity of flow

Which of these statements are correct?

1. 1, 2 and 3
2. 1 and 2 only
3. 2 and 3 only
4. 3 and 4

Q. Cavitation is likely to occur if

1. Pressure becomes very high.
2. Temperature becomes low.
3. Pressure at the specific point falls below vapour pressure.
4. Energy is released with the onset of a high intensity wave due to noise and vibration of the machine.

Which of the above statements are correct?

1. 1 and 3
2. 2 and 3
3. 3 and 4
4. 2 and 4

Q. A sluice inlet in a dam with streamlined entrance is shown in figure below.



If cavitation is expected to occur, it will first appear at the point

1. 1
2. 2
3. 3
4. 4

Q. Which one of the following statements is not correct?

1. Cavitation forms where the local pressure drops up to the vapour pressure conditions due to increase in local velocity.
2. Cavitation takes place in turbine blades, runners of pumps, spillways where local velocity increases considerably.
3. Cavitation may be prevented by maintaining the ambient pressure relatively higher at probable points of occurrence by raising their levels.
4. Boundaries likely to be affected by cavitation can be protected against pitting by covering it with tough materials like stainless steel or rubber.