JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech II MECHANICS OF FLUIDS Previous Question Paper (November/December - 2018 - R15)
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.
Part A
Define density.
Answer
Density is defined as the mass per unit volume of a substance. It is denoted by the Greek letter ρ (rho) and is expressed as ρ = m/V, where m is the mass and V is the volume. Its SI unit is kg/m³.
Define buoyancy.
Answer
Buoyancy is the upward vertical force exerted by a fluid on a body immersed in it. This force is equal to the weight of the fluid displaced by the body, as stated by Archimedes' principle. It acts through the center of buoyancy, which is the centroid of the displaced fluid volume.
Explain the concept of vorticity.
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Elaborate stream tube.
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What is Froude number?
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Explain viscometer.
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Differentiate pressure drag and friction drag.
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Define boundary layer.
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Write down the uses of Moody’s chart.
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Explain minor losses in pipe flow.
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Part B
Two large plane surfaces are 2.4 cm apart. The space between the surfaces is fixed with glycerine. What force is required to drag a very thin plate of surface area 0.5 square meter between the two large plane surfaces at a speed of 0.6 m/s, if the thin plate is in the middle of the two plane surfaces. Take the dynamic viscosity of glycerine is 0.810 Ns/m2.
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What do you understand by the hydrostatic equation? With the help of this equation derive the expressions for the total thrust on a sub-merged plane area and the buoyant force acting on a sub-merged body.
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An open circular cylinder of 15 cm diameter and 100 cm long contains water up to a height of 80 cm. find the maximum speed of which the cylinder is to be rotated about its vertical axis so that no water spills.
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Show that in case of forced vortex flow, the rise of liquid level at the ends is equal to the fall of liquid level at the axis of rotation.
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State Buckingham’s phi-theorem. Why this theorem is considered superior over the Rayleigh’s method for dimensional analysis.
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Explain distorted models and undistorted models. What is the use of distorted models?
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Explain various methods of preventing the separation of boundary layer.
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What do you mean by boundary layer separation? What is the effect of pressure gradient on boundary layer separation?
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What is Hagen Poiseuille’s formula? Derive an equation for Hagen Poiseuille’s formula.
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Prove that the maximum velocity in a circular pipe for viscous flow is equal to two times the average velocity of flow.
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