Kurukshetra University 2011-4th Sem B.Tech Mechanical Engineering Fluid mechanics b tech - Question Paper
Roll No. .'D.Cs.lft.'k&l........... Total No. of Pages : 3
BT-4/M11 8454Fluid Mechanics (w.e.f. 2006 onwards)
PaperME-208E, OptionI
Time : Three Hours] [Maximum Marks : 100
Note :Attempt FIVE questions in all, selecting at least ONE question from each unit.,
UNITI
1. (a) Differentiate between following :
(i) Kinematic and Dynamic Viscosity
(ii) Cohesion and Adhesion
(iii) Newtonian and Non-Newtonian fluid
(iv) Bulk modulus and compressibility of a fluid. 8 (b) Derive an expression for the depth of centre of pressure
from free surface of liquid of an inclined plane surface submerged in the liquid. 12
2. (a) Define and distinguish :
(i) Rotational and irrotational flow
(ii) Steady and Unsteady flow
(iii) Circulation and Vorticity. 9
(b) If the expression for stream function is described by
\|/ = x3-3xy2, determine whether flow is irrotational or rotational.If the flow is irrotational, then indicate the correct value of the velocity potential :
(i) - y3 - 3x2y
(ii) = - 3x2y. 11
3. (a) State and prove Bemoulis theorem. List the assumptions
made and limitations also. 8
(b) Describe an orificemeter and find an expression for measuring discharge of fluid through a pipe with this device. 6
(c) What is Pitot tube ? How is it used to measure velocity of flow at any point in a pipe or channel ? 6
4. (a) 360 litres per second of water is flowing an a pipe. The pipe
is bent by 120. The pipe bend measures 360 mm x 240 mm and volume of the bend is 0.14 m3. The pressure at the entrance is 72 kN/m2 and the exit is 2.4 m above the entrance section. Find the force exerted on the bend. 8
(b) Explain the following ,
(i) Tree and forced vortex flow
(ii) Kinetic energy correction factor ,
(iii) Momentum correction factor. 12
UNITin
5. (a) Derive Hagen-Poiseuille equation and state the assumptions
made. 12
(b) A liquid with a specific gravity 2.8 and a viscosity 0.8 poise flows through a smooth pipe of unknown diameter, resulting in a pressure drop of 800 N/m2 in 2 km length of the pipe. What is the pipe diameter if the mass flow rate is 2500 kg/h ? ' 8
6. (a) Explain in brief_
(i) Hydraulic Gradient Line (HGL)
(ii) Energy Gradient Line (EGL). 6 8454 2 (Contd.)
Derive an expression for the power transmission through the pipes. Find also the condition for maximum transmission of power. 6
Two pipes of diameter 400 mm and 200 mm each, 300 m long. When the pipes are connected in series the discharge through the pipe line is 0.10 m3/sec, find the loss of head incurred. What would be the loss of head in the system to pass the same total discharge when the pipes are connected in parallel ? Take friction factor = 0.0075 for each pipe.
(b)
(c)
7. (a)
(b)
(c)
8. (a) (b) ()
8
UNITIV
Discuss the following in regards to Boundary layer :
Jp Boundary layer thickness
(ii) Displacement thickness
(iii) Momentum thickness. 6 What is Blasius one seventh power law of velocity distribution.
8
What is laminar sublayer ? How this concept is useful ?
6
Distinguish between hydrodynamically smooth and rough boundaries. 6
Explain what is meant by separation of boundary layer. Describe with sketches the methods to control separation. 8
Differentiate between a streamlined body and a bluff body.
6
8454 3 6100+730-
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