Fluid Mechanics Assignment 4

Kathmandu University
Department of Chemical Science and Engineering

School of Engineering
Assignment – 4 CHEG 212 Fluid Mechanics Submission Date:
1. Explain boundary layer formation theorem in detail.

2. Find expression for
i) Shear stress,
ii) Velocity distribution,
iii) Maximum velocity and
iv) Average velocity, in case of flow of viscous fluid between two parallel plates.
3. What is Prandtl mixing length hypothesis?
4. Define Stoke’s law. Write the relation for frictional factor for both the cases of laminar and
turbulent flow.
5. Water at 40 0F of density 62.42 lb/ft3 and dynamic viscosity of 1.038 *10-3 lb/ft.sec is flowing
through a 0.12 inch diameter and 30 ft long horizontal pipe steadily at an average velocity of 3
ft/sec. Determine
i) Head loss
ii) Pressure drop and
iii) Pumping power requirement.
6. Air enter into diffuser with a velocity of 200 m/sec. Determine
i) Speed of sound
ii) The Mach number at the diffuser inlet when the air temperature is 30 0C.
7. Calculate the hydraulic diameter for turbulent fluid flow in a cross section which has
i) 2 in *10 in rectangle in full flowing condition
ii) An annulus with outside diameter 10 cm and inner diameter 8 cm
iii) 10 cm diameter tube flowing half full
8. An oil of viscosity 0.1 Ns/m2 and relative density 0.9 is flowing through a circular pipe of diameter
50 mm and of length 300 m. The rate of flow of fluid through the pipe is 3.5 litre/sec. Find the
pressure drop in a length of 300 m and also the shear stress at the pipe of wall.
9. A fluid of viscosity 0.7 Ns/m2 and specific gravity 1.3 is flowing through a circular pipe diameter
100 mm. The maximum shear stress at the pipe wall is given as 196.2 N/m2. Find
i) The pressure gradient,
ii) Average velocity, and
iii) Reynolds number of the flow.
10. Determine the Pressure gradient and the shear stress at the two horizontal parallel plates and the
discharge per metre width for the laminar flow of oil with a maximum velocity of 2 m/s and
viscosity 2.4525 Ns/m2 between two horizontal parallel fixed plates which are 100 m apart.
11. Prove the relation of fanning frictional factor given by f = 16/Nre
12. A sphere of diameter 1 mm falls through 335 m in 100 seconds in a viscous fluid. If the relative
densities of the sphere and the liquid are 7.0 and 0.96 respectively, determine the dynamic
viscosity of the fluid.
13. Find the head loss due to friction in a pipe of diameter 300 mm and length 50 m, through which
water is flowing at a velocity of 3 m/sec using Darcy formula and Chezy’s formula for which c =
60. Take kinematic viscosity = 0.01 stoke.
14. An oil of specific gravity 0.7 is flowing through a pipe of diameter 300 mm at the rate of 500
litre/sec. Find the head loss due to friction and power required to maintain the flow for a length
of 1000 m. Take kinematic viscosity as 0.29 Stoke.
15. The rate of flow of water through a horizontal pipe is 0.25 m3/sec. The diameter of the pipe which
is 200 mm is suddenly enlarged to 400 mm. The pressure intensity in the smaller pipe is 11.772
N/cm2. Determine
i) Loss of head due to sudden enlargement,
ii) Pressure intensity in the large pipe and
iii) Power lost due to enlargement.
16. Determine the rate of flow of water through a pipe of diameter 20cm and length 50 m when one
end of the pipe is connected to a tank and other end of the pipe is open to the atmosphere. The
pipe is horizontal and the height of water in the tank is 4 m above the centre of the pipe. Consider
all minor losses and take f = 0.009 in the Darcy formula.
17. A horizontal pipe line 40 m long is connected to a water tank at one end and discharges are freely
into the atmosphere at the other end. For the first 25 m of its length from the tank, the pipe is
150 mm diameter and its diameter is suddenly enlarged to 300 mm. The height of water in the
tank is 8 m above the centre line of pipe. Considering all possible losses, major and minor,
determine the rate of flow. Take f = 0.01 for both section of pipe.
18. A spherical steel ball of diameter 40 mm and of density 8500 kg/m3 is dropped in a large mass of
water. The co-efficient of drag of the ball in water is given as 0.45. Find the terminal velocity of
the ball in water. If the ball is dropped in air, find the increase in terminal velocity of ball. Take
density of air as 1.25 kg/m3 and CD as 0.1
19. A gas is flowing through a horizontal pipe at a temperature of 40 C. The diameter of the pipe is 8
cm and at a section 1-1 in this pipe, the pressure is 30.3 N/cm2 (gauge). The diameter of the pipe
changes from 8 cm to 4 cm at the section 2-2, where pressure is 20.3 N/cm2 (gauge). Find the
velocities of the gas at these sections assuming an isothermal process. Take R = 287.14 Nm/kg.K
and atmospheric pressure = 10 N/cm2.
20. An aeroplane is flying at an height of 15 km where the temperature is -500 C. The speed of the
plane is corresponding to M = 2.0. Assuming k =1.4 and R = 287 J/kg.K, find the speed of the plane.
“It is better to fail with originality than to succeed in imitation.”

Course Instructor: Er. Bijay Adhikari

Fluid Mechanics Assignment 4

Uploaded by

Copyright:

Available Formats

Fluid Mechanics Assignment 4

Uploaded by

Document Information

Original Description:

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

Fluid Mechanics Assignment 4

Uploaded by

Copyright:

Available Formats

Kathmandu University

Department of Chemical Science and Engineering

1. Explain boundary layer formation theorem in detail.

“It is better to fail with originality than to succeed in imitation.”

You might also like