Code No: 07A4EC15
Set No. 2
R07
in
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD II B.TECH II EXAMINATIONS MAY - 2010 II SEM–REGULAR/SUPPLEMENTARY B.Tech II Semester Regular Examinations,May 2010 MECHANICS OF FLUIDS Metallurgy And Material Technology Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ????? 1. (a) How the loss of energy at the entrance to the pipe and exit from the pipe is to be determined?
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(b) A horizontal pipeline 50 m long is connected to a water tank at one end and discharges freely into the atmosphere at the other end. For the first 30 m of its length from the tank, the pipe is 100 mm diameter and its diameter suddenly enlarged to 200 mm. The height of the water level in the tank is 10 m above the centre of the pipe. Determine the rate of flow. Take 4f = 0.04 for both sections of the pipe and consider minor losses. [6+10]
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2. (a) What is Pitot Tube? How will you determine the velocity at any point with the help of pitot tube.
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(b) A horizontal venturimeter with inlet and throat diameters 40cms and 20cms respectively is used to measure the flow of water. The reading of differential Manometer connected to the inlet and the throat is 18 cm of mercury. Determine the rate of flow. Take Cd =0.97 [7+9] 3. (a) How are the drag and lift forces caused on a body immersed in a moving fluid? (b) A flat plate 1.2 m × 1.2 m moves at 60 km per hour in a stationary air of density 1.15 kg/m3 . If the coefficient of drag and lift are 0.15 and 0.75 respectively, determine [6+10] The The The The
drag force lift force resultant force and power required to keep the plate in motion.
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i. ii. iii. iv.
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4. (a) In a three dimensional incompressible flow, the velocity components in y and z-direction are v = ax3 −by 2 +cz 2 ; w = bx3 −cy 2 +az 2 x. Determine the missing component of velocity distribution such that continuity equation is satisfied. (b) How is the continuity equation based on the principle of conservation of mass stated? And explain how the control volume approach will help indevicing continuity equation. [8+8]
5. (a) What is kinetic energy correction factor? (b) The water is flowing through a taper pipe of length 100m having diameters 600mm at the upper end and 300mm at the lower end, at the rate of 50 lit/ s. The pipe has a slope of 1 in 30. Find the pressure at the lower end if the pressure at the upper end is 19.62N/c m2 [7+9] 1
Code No: 07A4EC15
R07
Set No. 2
6. (a) The space between the two square flat parallel plates is filled with oil. Each side of the plate is 720 mm. The thickness of the oil film is 15 mm. The upper plate, which moves at 3 m/s requires a force of 120 N to maintain the speed. Determine: i. The dynamic viscosity of the oil, ii. The kinematic viscosity of oil if the specific gravity of oil is 0.95. [10+6]
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(b) State an d explain the Newton’s law of viscosity.
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7. Find the mass flow rate of air through venturimeter having inlet diameter as 400 mm and through diameter 200mm. The pressure at the inlet of the venturimeter is 27.468 N/ cm2 (abs) and temperature of a air at inlet is 200 C. The pressure at the throat is given as 25.506 N/ cm2 (abs ).Take R=287 J/Kg-K and K=1.4. [16] 8. (a) Define the terms Kinetic energy correction factor and momentum correction factor.
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(b) The Radial clearance between a hydraulic plunger and the cylinder wall is 0.1 mm, the length of the plunger is 300 mm and diameter 100 mm. Find the velocity of leakage and rate of leakage past the plunger at an instant when the difference of the pressure between the two ends of the plunger is 9m of water. Take mu = 0.0127 Poise. [6+10]
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Code No: 07A4EC15
R07
Set No. 4
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JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD II B.TECH II EXAMINATIONS MAY - 2010 II SEM–REGULAR/SUPPLEMENTARY B.Tech II Semester Regular Examinations,May 2010 MECHANICS OF FLUIDS Metallurgy And Material Technology Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ?????
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1. In a vertical pipe conveying oil of specific gravity 0.8 two pressure gauges, have been installed at A & B where the diameters are 16cms and 8cms respectively. A is 2m above B The pressure gauge reading have shown that the pressure at ‘B’ is greater than at ‘A’ by 0.981 N/cm2 . Neglecting all lasses, calculate the flow rate. If the gauges at A and B are replaced by tubes filled with the same liquid and connected to a U-tube contains mercury, calculate the difference of level of mercury in the two limbs of the U-tube. [16]
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2. (a) Explain briefly about the shock waves and how these shock waves are formed in convergent and divergent nozzle.
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(b) Find the velocity of air flowing at the outlet of a nozzle, fitted to a large vessel which contain air at a pressure of 294.3 N/cm2 (abs) and at a temperature of 200 C .The pressure at the outlet of the nozzle is 206 N/cm2 (abs). Take K=1.4 and R=287 J/ kg K. [8+8] 3. In a 450 bend a rectangular air duct of 1m2 cross-sectional area is gradually reduced to 0.5m2 area. Find the magnitude and direction of the force required to hold the duct in position .If the velocity of flow at the 1m2 section is 10m/s, and pressure is 2.943 N/cm2 .take density of air as 1.16 Kg/m3 . [16] 4. (a) Obtain the equation to the streamlines for the velocity field given as: V= 2 x3 i - 6 x2 yj
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(b) Differentiate between the Eulerian and Lagrangian methods of representing fluid flow. [8+8]
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5. (a) A 150mm diameter shaft rotates as 1500 r.p.m. in a 200mm long journal bearing with 150.5mm internal diameter. The uniform annular space between the shaft and the bearing is filled with oil of dynamic viscosity 0.8poise. Calculate the power dissipated as heat. (b) Define the following: i. ii. iii. iv.
[8+8]
Atmospheric pressure Gauge pressure Vacuum pressure Absolute pressure.
6. (a) Explain characteristics of laminar flow. Give examples where such a flow is encountered? 3
Code No: 07A4EC15
R07
Set No. 4
(b) A pipe of diameter 20 cm and length 200 m connecting two reservoirs, having difference of water level of 20m.Determine the discharge through the pipe. If an additional pipe of diameter 20 cm and length 1200m is attached to the last pipe 1200 m length of the existing pipe, find the increase in discharge. Take f=0.015 and neglect minor losses. [8+8]
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7. (a) What are different types of drag? What is streamlining? What is its effect on the Different types of drag?
(b) A cylinder 15 cm in diameter and 10 m long, is made to turn 1500 revolutions per minute with its axis perpendicular in a stream of air having uniform velocity of 25 m/sec. Assuming ideal fluid flow, find [8+8]
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i. Circulation ii. Lift force experienced by the cylinder and iii. The position of stagnation points Take density of air as 1.2 kg/m3 .
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8. (a) For sudden expansion in pipe flow, what is the optimum ratio between the diameter of the pipe before expansion and diameter pipe after expansion so that the pressure rise may be maximum.
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(b) Oil of specific gravity 0.5 flows in a 8 cm diameter pipeline. A sudden expansion takes place into a second pipeline of such diameter that the maximum pressure rise is obtained. If the rate of flow through the pipeline is 12.5 lt/sec, find the loss of energy in sudden expansion in centimetres of oil. [10+6]
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Code No: 07A4EC15
R07
Set No. 1
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JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD II B.TECH II EXAMINATIONS MAY - 2010 IISEM–REGULAR/SUPPLEMENTARY B.Tech II Semester Regular Examinations,May 2010 MECHANICS OF FLUIDS Metallurgy And Material Technology Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ?????
2. (a) Explain briefly about stagnation point?
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1. A Flow of 420 liters/min of oil of specific gravity 0.91 and viscosity 1.24 poise is pumped through a pipeline 75mm diameter having a length of 62m and whose outlet is 3m higher than its inlet. Estimate the power required for the pump if its efficiency is 60%. [16]
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(b) Avessel fitted with a nozzle, contains air at pressure of 2500KN/m2 and a temperature of 200 C.If the pressure at the outlet of the nozzle is 1750 KN/m2 find the velocity of air flowing at the outlet of the nozzle. Take K=1.4 and R=287 J/Kg K. [8+8] 3. (a) Derive an expression for the difference of pressure between two points in a free vertex flow.
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(b) A jet of water is initially 10cm in diameter and when directed vertically upward reaches a maximum height of 25m. Assuming the jet remains circular, determine the rate of water flowing and the diameter of the jet at a height of 15m. [7+9] 4. In a two-dimensional incompressible flow, the fluid velocity components are given by u=x-4y and v=-y-4x . Show that velocity potential exists and determine its form as well as stream function. [16]
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5. (a) What are the causes of loss of energy in pipe bends? Give expression to find loss of energy in pipe bends. (b) Particulars of three pipes connected in series are given below. Length(m) Diameter(mm) Friction coeeficient (4f) 100 100 0.02 120 75 0.028 90 60 0.032
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Pipe A B C
[8+8]
Find the size of a pipe of length 310 m whose pipe friction coefficient 4f = 0.024 equivalent to the compound pipe.
6. (a) Differentiate Notches and Weirs and classify the Notches? (b) The Coefficient of discharge for a venturimeter used for measuring the flow of an incompressible fluid was found to be constant when the rate of flow exceeded a certain volume. Show that under these conditions the loss of head hf in the convergent portion of venturimeter can be expressed as K1 Q2 . Where K1 is a constant. [7+9] 5
Code No: 07A4EC15
R07
Set No. 1
7. (a) A lubricating oil of viscosity µ undergoes steady shear between a fixed lower plate and an upper plate moving at speed V. The clearance between the plates is t. Show that a linear velocity profile results if the fluid does not slip at either plate.
8. (a) Differentiate between pressure drag and shear drag. (b) A 3 mm diameter lead shot drops into water. Calculate
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(b) Describe with a neat sketch a micro-manometer used for very precise measurement of small pressure difference between two points. [8+8]
[6+10]
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i. The drag force exerted by water as the lead shot reaches its terminal Velocity ii. The surface and pressure drags and iii. The terminal velocity reached. Take specific gravity of lead = 11.5 and viscosity of water = 0.001 N-sec / m2 .
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Code No: 07A4EC15
Set No. 3
R07
in
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD II B.TECH IIIISEM–REGULAR/SUPPLEMENTARY EXAMINATIONS MAY - 2010 B.Tech II Semester Regular Examinations,May 2010 MECHANICS OF FLUIDS Metallurgy And Material Technology Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ?????
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1. The following data relates to an inclined venturimeter diameter of the pipeline =400mm: Inclination of the pipeline with the horizontal= 300 ;Throat diameter =200 mm. The distance between the mouth and throat of the meter =600mm, specific gravity of oil flowing through the pipeline =0.7, specific gravity of heavy liquid (U-tube) =13.6:The reading of differential manometer =50 mm. The coefficient of the meter =0.98 Determine the rate of flow in the pipeline. [16] 2. (a) Explain with a neat sketch the boundary layer characteristics when a fluid is flowing over a flat plate.
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(b) A thin flat plate 0.3 m wide and 0.6 m long is suspended and exposed parallel to air flowing with a velocity of 3 m/sec. Calculate drag force on both sides of the plate when the 0.3 m edge is oriented parallel to free stream. Consider flow to be laminar and assume for air kinematic viscosity is 0.18 stokes and density is 1.2 kg/m3 . [10+6] 3. (a) What do you meant by viscous flow? Mention various forces to be considered in Navier Stroke’s equation. (b) Through a horizontal circular pipe of diameter 100 mm and of length 10m, an oil of dynamic 0.097 poise and relative density 0.9 is flowing. Calculate the difference of pressure at the two ends of the pipe, if 100 Kg. of the oil is collected in a tank in 30 seconds. [10+6] 4. (a) Derive equation of motion of Forced Vertex Flow.
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(b) A 30cm diameter pipe carries water under a head of 15m with a velocity of 4m/s. If the axis of the pipe turns through 450 ,find the magnitude and direction of the resultant force at the bend. [8+8]
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5. (a) Derive an expression for calculating time of rolling of floating body. (b) Expalin why in liquids, the viscosity decreases when the temperature is increased where as it increases in the case of gases. [8+8]
6. (a) Derive an expression for the head loss due to sudden enlargement in pipe flow and there from deduce the head loss due to sudden contraction. (b) A horizontal pipeline 200 mm in diameter is joined by sudden enlargement to 300 mm diameter. When the flow is from smaller to larger cross section, the head loss is 0.6 m in excess of that when the flow takes from larger to smaller section (sudden contraction). Determine the flow rate. Take coefficient of contraction Cc = 0.68. [8+8] 7
Code No: 07A4EC15
R07
Set No. 3
7. (a) The Velocity components in x and y directions are given as 2yx3 2xy 3 2 . Indicate whether the given velocity distribution u = 3−x 2 y and v = xy − 3 is: i. a possible field of flow. ii. Not a possible field of flow. [8+8]
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(b) Is the flow-net analysis applicable to rotational flow? If no, why?
8. (a) what is the relation between pressure and density of a compressible fluid for? i. Isothermal process ii. Adiabatic process.
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(b) A gas is flowing through a horizontal pipe at a temperature of 40 C. The diameter of the pipe is 8cm and at a section I in the pipe, the pressure is 30.3N/cm2 (gauge). The diameter of the pipe changes from 8cm to 4cm at the section II, where pressure is 20.3N/cm2 (gauge). Find the velocities of the gas at these sections assuming an isothermal process. Take R=287.14Nm/Kg.K and atmosphere pressure=10N/ cm2 . [6+10]
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