JNTU
JNTU B.Tech II MECHANICS OF FLUIDS AND HYDRAULIC MACHINES Previous Question Paper (May - 2019 - R13)
Part A is compulsory. Answer any one full question from each unit in Part B.
Part A
Define specific volume and specific density of a fluid.
Answer
Specific volume is the volume occupied by a unit mass of fluid, defined as the reciprocal of density (v = 1/ρ). Specific density (commonly referred to as specific gravity) is the ratio of the density of a fluid to the density of a standard fluid (water at 4°C for liquids) at a specified temperature.
Differentiate between absolute and gauge pressure.
Answer
Absolute pressure is the pressure measured relative to a perfect vacuum (zero pressure). Gauge pressure is the pressure measured relative to the local atmospheric pressure. The relationship is expressed as: Absolute Pressure = Atmospheric Pressure + Gauge Pressure.
List the general characteristics of laminar flow.
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Give two examples of unsteady and non-uniform flow.
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What do you understand by the term major losses and minor losses?
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What is hydraulic gradient line?
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Define geometric similarities.
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What is water hammer?
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What are the main parts of reciprocating pumps?
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Define mechanical efficiency.
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Part B
A piston of 2.5 kg having diameter and height 4 cm and 7 cm respectively is decelerating at rate of 1 m/s2 in a hollow lubricated cylinder. The clearance between piston and hollow cylinder is 1.5 mm. Calculate the viscosity of the film when the velocity of piston is 8 m/s.
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What is meant by vapour pressure? Explain its importance in liquid flow systems.
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What is difference between U-tube differential manometers and inverted U-tube differential manometers?
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Air is introduced through a nozzle into a tank of water to form a stream of bubbles. If the bubbles are intended to have a diameter of 2 mm, calculate by how much the pressure of air at the nozzle must exceed that of surrounding water. Assume σ = 72.7 × 10-3 N/m.
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Define equation of continuity. Obtain the expression for continuity equation for a three-dimensional flow.
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Define stream line, streak line and path line. Derive mathematical expression for each of these lines.
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What is Euler’s equation of motion? How will you obtain Bernoulli’s equation from it?
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Explain momentum of equation and give its application on force on pipe bend.
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Two reservoirs whose water surface elevations differ by 100 m are connected by a 25 cm diameter pipe 3000 m long. Another pipe of the same diameter is laid parallel with the first pipe and connected to the middle one-third of its length. Calculate the percent increase in discharge. Assume f=0.01 for all pipes and neglect minor losses.
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Explain clearly the concepts of displacement and momentum thickness of a boundary layer.
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An orifice in one side of a large tank is rectangular in shape, 3 meters broad and 1 m deep. The water level on one side of the orifice is 4 meters above its top edge. The water level on the other side of the orifice is 0.5 meter below its top edge. Calculate the discharge through the orifice per second if Cd = 0.63.
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What is venturimeter? Derive an expression for the discharge through a venturimeter.
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Find an expression for the efficiency of a series of moving curved vanes when a jet of water strikes vanes at one of its tips. Prove that maximum efficiency is when u = V and the value of maximum efficiency is 50%.
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Explain water hammer with control measure.
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What is the main difference between a Francis and propeller turbine? How are hydraulic losses minimized in propeller turbine?
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How are work output and hydraulic efficiency calculated from velocity diagram?
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Discuss the classification of centrifugal pumps as per specific speed, working head and pump construction.
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Explain the different types of pump characteristics.
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Explain the working of reciprocating pump.
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Find the slip of the reciprocating pump in percentage when a single-acting pump cylinder diameter is 0.3 m, stroke length 0.25 m. The pump run at 45 rpm and actual discharge is 0.0128 m3/sec.
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