Fluid Mechanics Sheet 28
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1) Question.
Assertion A: Water hammer occurs when the quick-acting valve at the end of a long pipeline is suddenly closed.
Reason R: Surge tanks are provided in penstocks to relieve the penstock of high water hammer pressure when the flow into a turbine is stopped due to low power demand.
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2) Question.
Assertion A: Continuity equation must hold good in a pipe network system.
Reason R: In a pipe network analysis, the flow into any junction must be equal to the flow out of the junction.
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3) Question.
Assertion A: There is no flow in the direction perpendicular to a stream line at any point on it
Reason R: Stream line consists of a number of infinitesimally small segments such that all of them lie along the directions of velocity vectors of fluid particles at those segments
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4) Question.
Assertion A: The movement of two blocks of wood wetted with hot glue requires greater and greater effort as the glue is drying up.
Reason R: Viscosity of liquids varies inversely with temperature.
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5) Question.
Assertion A: A minor change in specific energy at or close to critical state will cause a major change in depth.
Reason R: A critical state of flow is characterized by its Froude number being equal to unity.
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6) Question.
Assertion A: The inlet velocity triangle for a Pelton turbine is a straight line
Reason R: For a Pelton turbine, the vane angle at inlet is
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7) Question.
Assertion A: Irrotational flow exists when the net rotation of the fluid about its mass centre is zero.
Reason R: There is always a possibility of rotation in ideal fluid and therefore, ideal fluids cannot have irrotational flow.
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8) Question.
Assertion A: In the equation , for laminar flow through the pipe, the term v (mean velocity of flow) is given by
Reason R: The term 'f' (friction factor) in the above equation equals