Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2018 Winter 7th Sem New 2170106 Boundary Layer Theory Previous Question Paper
1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?VII (NEW) EXAMINATION ? WINTER 2018
Subject Code: 2170106 Date: 03/12/2018
Subject Name: Boundary Layer Theory
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) 1.Define Laminar boundary layer
2. Define Boundary Layer thickness
3.Write an equation for Reynolds number
03
(b) Draw and explain Velocity profile and Temperature profile for Flat
plate.
04
(c) Derive an expression for the Darcy weisbach equation for turbulent
boundary layer flow.
07
Q.2 (a) Explain Reynolds expression for turbulent shear stress. 03
(b) Define smooth and rough boundaries with sketches. 04
(c) Derive velocity defect equations for turbulent flow in pipe. 07
OR
(c) Derive orr-sommer field equation. 07
Q.3 (a) Define Momentum thickness and energy thickness with equations. 03
(b) Pipe line carrying water has average height if irregularities projecting
from the surface of the boundary of the pipe as 0.15 mm. what type of
boundary is it? The shear stress developed is 4.9 N/m
2
. The kinematic
viscosity of water is 0.01 stokes.
04
(c) Derive Blasius exact solution for laminar boundary layer flows. 07
OR
Q.3 (a) Explain wind tunnel turbulence. 03
(b) Explain critical Reynolds number. 04
(c) Write a short note on Relaminarization. 07
Q.4 (a) Explain Colburn analogy. 03
(b) Discuss flow over a cylinder with neat sketch. 04
(c) Derive an equation for Couette flow. 07
OR
Q.4 (a) Explain Reynolds analogy. 03
(b) Draw thermal boundary layer growth and thermal profile over the hot
surface.
04
(c) A rough pipe is of diameter 8 cm. the velocity at a point 3 cm from wall
is 30% more than the velocity at a point 1 cm from pipe wall. Determine
the average height of the roughness.
07
Q.5 (a) List out Different kinds of boundary layer control. 03
(b) Explain boundary layer on a flat plate 04
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1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?VII (NEW) EXAMINATION ? WINTER 2018
Subject Code: 2170106 Date: 03/12/2018
Subject Name: Boundary Layer Theory
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) 1.Define Laminar boundary layer
2. Define Boundary Layer thickness
3.Write an equation for Reynolds number
03
(b) Draw and explain Velocity profile and Temperature profile for Flat
plate.
04
(c) Derive an expression for the Darcy weisbach equation for turbulent
boundary layer flow.
07
Q.2 (a) Explain Reynolds expression for turbulent shear stress. 03
(b) Define smooth and rough boundaries with sketches. 04
(c) Derive velocity defect equations for turbulent flow in pipe. 07
OR
(c) Derive orr-sommer field equation. 07
Q.3 (a) Define Momentum thickness and energy thickness with equations. 03
(b) Pipe line carrying water has average height if irregularities projecting
from the surface of the boundary of the pipe as 0.15 mm. what type of
boundary is it? The shear stress developed is 4.9 N/m
2
. The kinematic
viscosity of water is 0.01 stokes.
04
(c) Derive Blasius exact solution for laminar boundary layer flows. 07
OR
Q.3 (a) Explain wind tunnel turbulence. 03
(b) Explain critical Reynolds number. 04
(c) Write a short note on Relaminarization. 07
Q.4 (a) Explain Colburn analogy. 03
(b) Discuss flow over a cylinder with neat sketch. 04
(c) Derive an equation for Couette flow. 07
OR
Q.4 (a) Explain Reynolds analogy. 03
(b) Draw thermal boundary layer growth and thermal profile over the hot
surface.
04
(c) A rough pipe is of diameter 8 cm. the velocity at a point 3 cm from wall
is 30% more than the velocity at a point 1 cm from pipe wall. Determine
the average height of the roughness.
07
Q.5 (a) List out Different kinds of boundary layer control. 03
(b) Explain boundary layer on a flat plate 04
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2
(c) Air at 20
0
C and at a pressure of 1 bar is flowing over a flat plate at a
velocity of 3m/s. If the plate is 280mm wide and at 56
0
C, calculate the
following quantities at x=280mm
1.Average friction coefficient
2.Shearing stress due to friction
3.Thickness of thermal boundary layer
4.Local convective heat transfer coefficient
5.Average convective heat transfer coefficient
Take, Density of air is 1.1374kg/m
3
, K=0.02732 W/m
0
C,
Cp=1.005kJ/kgK, Kinematic viscosity=16.768*10
-6
m
2
/s, Pr=0.7
07
OR
Q.5 (a) Discuss causes of boundary layer separation. 03
(b) Air at 20
0
C and at a pressure of 1 bar is flowing over a flat plate at a
velocity of 3m/s. If the plate is 280mm wide and at 56
0
C, calculate the
following quantities at x=280mm
1. Boundary layer thickness
2. Local friction coefficient
Take, Kinematic viscosity=16.768*10
-6
m
2
/s,
04
(c) Derive Momentum equations for boundary layer by von- karman. 07
*********
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This post was last modified on 20 February 2020