JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech II FLUID MECHANICS AND OPEN CHANNEL HYDRAULICS Previous Question Paper (October - 2020 - R13)
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Main
Calculate the capillary effect in mm in a glass tube 3 mm in diameter when immersed in (i) water (ii) mercury. Both the liquids are at 20°C and the values of the surface tensions for water and mercury at 20°C in contact with air are respectively 0.0796 N/m and 0.51 N/m. Contact angle for water = 0° and for mercury = 130°.
Answer
The capillary rise or depression is given by the formula:
Where σ is surface tension, θ is the contact angle, ρ is density, g is acceleration due to gravity (9.81 m/s²), and d is the diameter (0.003 m).
(i) For Water: σ = 0.0796 N/m, θ = 0°, ρ = 998 kg/m³. Substituting values:
(ii) For Mercury: σ = 0.51 N/m, θ = 130°, ρ = 13546 kg/m³. Substituting values:
Define density and specific volume. What is the relation between them?
Answer
Density (Mass Density) is defined as the mass of a fluid per unit volume. It is denoted by ρ (rho) and has units of kg/m³.
Specific Volume is defined as the volume of a fluid occupied by a unit mass. It is the reciprocal of density, denoted by v, and has units of m³/kg.
The mathematical relation between them is:
Explain how vacuum pressure can be measured with the help of a U-tube manometer.
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Explain Eulerian method of describing fluid flow.
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What is pitot-tube? How will you determine the velocity at any point with the help of pitot-tube?
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A 200 mm × 100 mm venturimeter is provided in vertical pipe carrying water, flowing in the upward direction. A differential mercury manometer connected to the inlet and throat gives a reading of 220 mm. Find the rate of flow. Assume Cd = 0.98.
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Derive the expression Cd = Cc × Cv.
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What are the advantages of triangular notch or weir over rectangular notch?
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The head of water over a rectangular weir is 50 cm. The length of the crest of the weir with end contraction suppressed is 1.4 m. Find the discharge using Francis’s Formula.
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Explain the determination of velocity of approach.
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What is a compound pipe? How would you determine the equivalent size of a compound pipe?
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Deduce the condition for most economical section of a rectangular channel.
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