JNTU
JNTU B.Tech II FLUID MECHANICS II Previous Question Paper (February - 2024 - R16)
Question paper consists of Part A, Part B. Part A is compulsory, which carries 25 marks. In Part A, answer all questions. In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
Part A
Write any four applications of Hydraulic Jump.
Answer
The four primary applications of a hydraulic jump are:
- To dissipate excess kinetic energy of flowing water downstream of hydraulic structures like spillways and sluice gates to prevent downstream bed erosion.
- To increase the water level on the downstream side of a structure for irrigation or water distribution purposes.
- To facilitate the mixing of chemicals in water treatment processes by creating high turbulence.
- To act as a device for measuring discharge in open channels by relating the jump characteristics to the upstream flow conditions.
What is critical depth in open channel flow? Can open channel flow be laminar?
Answer
Critical depth is the depth of flow at which the specific energy of the fluid is at its minimum for a given discharge. At this depth, the Froude number of the flow is exactly equal to unity, representing the transition state between subcritical and supercritical flow regimes.
Yes, open channel flow can be laminar. While most practical engineering applications involve turbulent flow due to high velocities and large hydraulic radii, laminar flow occurs when the Reynolds number is very low, typically below 500 to 600. This is occasionally observed in laboratory experiments with highly viscous fluids or in thin-film flows over smooth surfaces.
Define and explain the term similitude.
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State and explain the significance of Buckingham’s pi theorem.
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Define Impulse Momentum Principle.
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Derive an expression for Force exerted by a jet on a stationary curved plate.
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Define the term impact of jet.
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Find the force exerted by a jet of water of diameter 70 mm on a stationary flat plate, normally with a velocity of 25m/s.
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Define the terms, Slip and Negative slip in pumps.
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Why pumps are generally less efficient than turbines.
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Part B
Explain velocity distribution in open channel flow.
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Discuss about types of Channels.
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What is Chezy’s formula for determining the velocity of an open channel flow?
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An irrigation channel of trapezoidal section, having side slope 3 horizontal to 2 vertical, is to carry a flow of 10 cumecs on a longitudinal slope of 1 in 5000. The channel is to be lined for which the value of friction coefficient in Manning’s formula is n = 0.012. Find the most economical section of channel.
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Explain Rayleigh’s method for Dimensional analysis.
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The resisting force R of a supersonic plane during flight can be considered as dependent upon the length of the aircraft l, velocity V, air viscosity μ, air density ρ and bulk modulus of air is k. Express the functional relationship between the variables and the resisting force.
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Explain the following in fluid flow:
Reynolds Number
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Euler’s Number
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Mach ‘s Number
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Weber’s Number
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Derive an expression for force exerted by the jet of water on moving curved plate.
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A jet of water of diameter 100 mm strikes a curved plate at its centre with a velocity of 15 m/sec. The curved plate is moving with a velocity of 7 m/sec in the direction of the jet. The jet is deflected through an angle of 1500. Assuming the plate is smooth find:
force exerted on the plate in the direction of the jet
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power of the jet
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efficiency
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A Pelton wheel has a mean bucket speed of 10 m/sec with jet of water flowing at the rate of 700 L /s under a head of 30 meters. The buckets deflects the jet trough an angle of 1600. Calculate the power given by water to the runner and the hydraulic efficiency of the turbine. Assume coefficient of velocity as 0.98
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Impulse and Reaction turbine
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Radial and Axial flow Turbines
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Inward and Outward Radial flow turbines
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Explain the multistage pumps with impellers in series and parallel.
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A centrifugal pump is to discharge 0.118 m3 / sec at a speed of 1450 rpm against a head of 25 m. The impeller diameter at outlet is 250 mm and its width at outlet is 50 mm and manometric efficiency is 75 %. Determine vane angle at outer periphery of the impeller
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