Jawaharlal Nehru Technological University Hyderabad
Jawaharlal Nehru Technological University Hyderabad B.Tech II Year I Semester FLUID MECHANICS Previous Question Paper (April/May - 2023 - R18)
Note: i) Question paper consists of Part A, Part B. ii) Part A is compulsory, which carries 25 marks. In Part A, Answer all questions. iii) 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
Define compressibility and bulk modulus.
Answer
Compressibility is the reciprocal of bulk modulus, representing the measure of a fluid's change in volume due to pressure changes. Bulk modulus (K) is defined as the ratio of compressive stress to volumetric strain, given by K = -dp / (dV/V).
Distinguish between gauge pressure and vacuum pressure.
Answer
Gauge pressure is the pressure measured above atmospheric pressure, while vacuum pressure is the pressure measured below atmospheric pressure. Gauge pressure is always positive, whereas vacuum pressure is expressed as a negative gauge value.
List out the properties of velocity potential function. What is the relationship between stream function and velocity potential function?
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What is circulation?
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What are the advantages of triangular notch or weir over rectangular notch or weir?
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What are the advantages of venturimeter over orifice meter?
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Using Darcy and Hagen-Poiseuille equations, derive expression for friction factor.
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What is the hydraulics of flow through parallel pipes?
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Define the term boundary layer and boundary layer theory.
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Define displacement thickness.
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Part B
A cube of side 100 mm and weight 5 N is immersed in a liquid of relative density 0.80 contained in a rectangular tank of plan area 150 mm × 150 mm. If tank contained liquid to a height of 80 mm before the immersion of cube, determine the levels of bottom of cube and the liquid surface.
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Define pressure. Obtain an expression for the pressure intensity at a point in a fluid.
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A metal ball weighs 9500 N in air and 8000 N in water. Find out its volume and specific gravity.
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An oil film of thickness 1.5 mm is used for lubrication between a square plate of size 0.9 m × 0.9 m and an inclined plane having an angle of inclination 20°. The weight of the square plate is 392.4 N and it slides down the plane with a uniform velocity of 0.2 m/s. Find the dynamic viscosity of the oil.
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Explain about velocity potential function and stream function.
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Define the equation of continuity. Obtain the expression for continuity equation in three dimensions.
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The flow field of a fluid is given by V= xy i + 2yz j– (yz + z2) k. Show that it represents a possible three dimensional steady incompressible continuous flow.
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Explain flow net analysis.
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A right angled V-notch is used for measuring a discharge of 30 litre/sec an error of 2 mm was made in measuring the head over the notch. Calculate the percentage error. Take Cd=0.62.
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Define momentum equation and its applications.
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A horizontal pipe of diameter 100 mm is fitted to a tank containing oil of relative density 0.80. At the end of pipe, a nozzle of diameter 25 mm is fitted. The head acting on the pipe is 4 m. Determine discharge from the nozzle and pressure at the base of nozzle. The energy loss in the pipe can be taken as 20 times the velocity head in pipe and neglecting energy loss in the nozzle.
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Define velocity of approach. How can you account for it while computing the discharge over weirs?
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Two reservoirs 1 and 2 having 15.5 m difference of water levels are connected by a pipeline ABC. The elevation of point B being 4 m below the level of water in reservoir 1. The length AB of the pipeline is 250 m and is made of steel and length BC of pipeline is 450 m and is made of cast iron. The diameter of both pipes is 200 mm. A partially closed valve is located in pipe BC at a distance of 150 m from reservoir 2. If flow through the pipeline is 3000 litres per minute, the pressure head at B is 0.50 m and head loss at the valve is 5 m. Find friction factors of two pipes and draw HGL and TEL.
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Derive Darcy equation. What are the various head losses in pipes and pipe fitting?
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Derive an expression for loss of head due to sudden enlargement.
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Obtain an expression for the boundary shear stress in terms of momentum thickness.
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What do you mean by separation of boundary layer? What is the effect of pressure gradient on boundary layer separation?
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What are the different methods of preventing the separation of boundary layers?
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Define laminar boundary layer, turbulent boundary layer, laminar sub layer and boundary layer thickness?
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