JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech II Year MECHANICS OF FLUIDS Previous Question Paper (April/May - 2018 - R13)
Note: This question paper contains two parts A and B. Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks and may have a, b, c as sub questions.
Part A
Determine the specific gravity of a fluid having viscosity 0.05 poise and kinematic viscosity 0.035 stokes.
Answer
Given: dynamic viscosity μ = 0.05 poise = 0.005 Ns/m2; kinematic viscosity ν = 0.035 stokes = 0.0000035 m2/s. Using the relation ν = μ / ρ, the density of the fluid is ρ = μ / ν = 0.005 / 0.0000035 = 1428.57 kg/m3. The specific gravity S = ρ / ρwater = 1428.57 / 1000 = 1.428.
Define the terms center of pressure and total pressure on an immersed body.
Answer
Total pressure is the total force exerted by a static fluid on an immersed surface. The center of pressure is the point of application of this resultant total pressure force on the surface.
Define the terms vorticity and Stream function.
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Define the terms velocity potential function.
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Explain the momentum of equation.
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What do you mean by fully developed flow?
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What is meant by boundary layer? Why does it increase with distance from the upstream edge?
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Define the terms, Skin friction drag and Velocity profile.
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Explain the significance of Moody’s chart.
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The friction factor in a laminar flow through a pipe is 0.016. What is Reynold’s number?
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Part B
Prove that the centre of pressure of a completely sub-merged plane surface is always below the centre of gravity of the sub-merged surface or at most coincide with the centre of gravity when the plane surface is horizontal.
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What is differential manometer? Explain the working principle of U-tube differential manometer with a sketch?
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Explain: i) Newtons law of viscosity ii) Surface Tension and iii) Capillarity.
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The relative location of centre of buoyancy with respect to the center of gravity is not considered as a criterion for stability of floating bodies. Why?
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Obtain expressions for stream and velocity potential functions.
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Distinguish between rotational flow and irrotational flow. Give one example of each.
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Check whether the following sets of velocity components satisfy the continuity equation of steady, incompressible flow u = x2 – y2, v = x – 2xy.
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Derive continuity equation for 2D flow.
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State Bernoulli’s theorem. Mention the assumptions made.
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An oil of sp.gr.0.8 is flowing through a venturimeter having inlet diameter 20 cm and throat diameter 10 cm. The oil- mercury differential manometer shows a reading of 25 cm. Calculate the discharge of oil through the horizontal venturimeter. Take Cd =0.98.
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State and explain Buckingham’s π-theorem.
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Explain the concept of similarities and explain the types of similarities.
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Consider a steady, laminar, constant density boundary flow over a flat plate. Find the ratio of skin friction drag on the front half of the plate to that on the rear half.
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What are the different methods of preventing the separation of boundary layer?
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What are the factors affecting boundary layer thickness? Explain.
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Discuss the concept of boundary layer with reference to fluid motion over a flat plate.
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Describe briefly about Reynold’s experiment.
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Explain how a fully developed flow is formed?
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What is minor loss in pipe flows? Under what conditions does minor losses become major losses?
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Derive Darcy’s equation.
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