MGTO 121 SAMPLE MIDTERM (Student ID #): _ Part I. Multiple Choice. For the following multiple choice questions, choose the one answer that is the best answer to the question. Each question is worth 2 points, for a total of 30 points for the section. Pleas
Problem 9.32
[Difficulty: 3]
Given: Find:
Blasius exact solution for laminar boundary layer flow (a) Evaluate shear stress distribution (b) Plot /w versus y/ (c) Compare with results from sinusoidal velocity profile: u 2 y U We will apply the shear stress
Problem 11.26
[Difficulty: 3]
Given: Find: Solution:
Basic equation:
Data on wide channel Stream depth after rise
p1 g
+
V1
2
2 g
+ y1 = + + y2 + h 2 g g
p2
V2
2
The Bernoulli equation applies because we have steady, incompressible, frictionless flow. Not
Problem 9.30
[Difficulty: 2]
Given: Find: Solution:
Blasius exact solution for laminar boundary layer flow Plot and compare to parabolic velocity profile: u U 2
y
y
2
The Blasius solution is given in Table 9.1; it is plotted below.
Parabolic Blasius
0
Problem 13.158
[Difficulty: 3]
Given: Air flow through a duct with heat transfer Find:
Heat addition needed to yield maximum static temperature and choked flow
Solution:
The given or available data is: R = cp = k = D= V1 = p1 = T1 = T1 = 53.33 0.2399 1.4
Problem 2.18
[Difficulty: 2]
Given:
Time-varying velocity field
Find:
Streamlines at t = 0 s; Streamline through (3,3); velocity vector; will streamlines change with time
Solution:
v
For streamlines
u
=
dy
At t = 0 (actually all times!)
dx
dy
So, separati
Problem 11.25
[Difficulty: 3]
Given: Find: Solution:
Basic equation:
Data on rectangular channel and a bump Local change in flow depth caused by the bump
p1 g
+
V1
2
2 g
+ y1 = + + y2 + h 2 g g V
2
p2
V2
2
The Bernoulli equation applies because we have st
Problem 12.50
x
[Difficulty: 3]
h
Given: Find: Solution:
Basic equations:
Supersonic aircraft flying overhead Time at which airplane heard
c
k R T m s
M
V c
asin k 1.4 x V
1
M
R 286.9 J kg K
Given or available data
V 1000
h 3 km
The time it takes to fl
Problem 13.160
[Difficulty: 2]
Given: Find: Solution:
Frictionless air flow in a pipe Heat exchange per lb (or kg) at exit, where 500 kPa
Basic equations: mrate V A
p R T
Q dm
cp T02 T01
(Energy)
p 1 p 2 1 V1 V2 V1 (Momentum) p 2 500 kPa J kg K R 286.9 c
Problem 2.20
[Difficulty: 3]
Given:
Velocity field
Find:
Plot of pathline traced out by particle that passes through point (1,1) at t = 0; compare to streamlines through
same point at the instants t = 0, 1 and 2s
Solution:
up =
dx
dt
= B x ( 1 + A t)
A =
Problem 13.58
[Difficulty: 3]
Given: Find: Solution:
Basic equations:
Rocket motor on test stand Mass flow rate; thrust force
k
T0 T
1
k1 2
M
2
p0 p
1
k1 2
M
2
k 1
p R T
c
k R T
mrate A V
patm pe Ae Rx mrate Ve
Given or available data p e 75 kPa d 25
Problem 12.51
[Difficulty: 3]
x
h x = Vt
Given: Find: Solution:
Basic equations:
Supersonic aircraft flying overhead Location at which first sound wave was emitted
c
k R T m s
M
V c
asin k 1.4
M
1 R 286.9 J kg K
Given or available data
V 1000
h 3 km x h
Problem 11.27
[Difficulty: 2]
Given: Find: Solution:
Basic equation:
Data on sluice gate Water level upstream; Maximum flow rate
p1 g
+
V1
2
2 g
+ y1 = + + y2 + h 2 g g
p2
V2
2
The Bernoulli equation applies because we have steady, incompressible, frictio
Problem 9.31
[Difficulty: 3]
Given: Find:
Blasius exact solution for laminar boundary layer flow (a) Evaluate shear stress distribution (b) Plot /w versus y/ y u (c) Compare with results from sinusoidal velocity profile: sin U 2 We will apply the shear st
Problem 13.159
[Difficulty: 2]
Given: Find: Solution:
Frictionless flow of Freon in a tube Heat transfer; Pressure drop NOTE: 2 is NOT as stated; see below
Basic equations: mrate V A
p R T
Q mrate h 02 h 01 lbm ft
2 3
h0 h
V
2
2 BTU lbm
2 2
p 1 p 2 1 V1
Problem 2.19
[Difficulty: 3]
Given:
Velocity field
Find:
Plot of pathline traced out by particle that passes through point (1,1) at t = 0; compare to streamlines through same
point at the instants t = 0, 1 and 2s
Solution:
Governing equations:
up =
For pa
Problem 9.125
[Difficulty: 2]
Given: Find: Solution:
A runner running during different wind conditions. Calories burned for the two different cases
Governing equation:
CD
FD 1 V 2 A 2
FD
1 C D V 2 A 2
Assumption: 1) CDA = 9 ft2 2) Runner maintains speed
Problem 9.29
[Difficulty: 5]
Given:
Air flow in laboratory wind tunnel test section.
Find: Solution: Governing Equations:
(a) Displacement thickness at station 2 (b) Pressure drop between 1 and 2 (c) Total drag force caused by friction on each wall We wil
Problem 11.23
[Difficulty: 3]
Given: Find: Solution:
Basic equation:
Data on rectangular channel and a bump Elevation of free surface above the bump
p1 g
+
V1
2
2 g
+ y1 = + + y 2 + h The Bernoulli equation applies because we have steady, 2 g g incompress
Problem 9.123
[Difficulty: 1]
Given: Find: Solution:
Basic equation:
Data on wind turbine blade Bending moment
FD V
1 2 FD A V CD 2 V 85 knot 143.464 A L W 0.00233 ReL CD V L 0.0742
1 5
y
ft s L 1.5 ft A 172.5 ft
2 2
The given or available data is
W 115 f
Problem 13.155
[Difficulty: 4]
Given: Air flow from converging-diverging nozzle into heated pipe Find:
Plot Ts diagram and pressure and speed curves
Solution:
The given or available data is: R = k = cp = T0 = p0 = pe = Equations and Computations: From p 0
Problem 3.18
[Difficulty: 2]
Given:
Data on partitioned tank
Find:
Gage pressure of trapped air; pressure to make water and mercury levels equal
Solution:
The pressure difference is obtained from repeated application of Eq. 3.7, or in other words, from Eq