ME 113 Winter 2015
Midterm Exam 02/04/2015
NAME: _
Discussion Session: _
Instructions (Read Carefully):
On the top margin of each page write:
o Your initial
o Your discussion section (M-11AM / M-1PM / W-1PM)
o Midterm
The exam is closed-book and closed-no
Problem 5.1
[Difficulty: 1]
The list of velocity fields provided above
Given:
Which of these fields possibly represent two-dimensional, incompressible flow
Find:
We will check these flow fields against the continuity equation
Solution:
Governing
u v w 0 (
Problem 3.52
Given:
Geometry of plane gate
Find:
[Difficulty: 3]
Minimum weight to keep it closed
L=3m
h
y
L/2
dF
W
w=2m
Solution:
FR = p dA
Basic equation
MO = 0
FR = pc A
or, use computing equations
dp
= g
dh
Ixx
y' = yc +
A yc
Assumptions: static fluid
Problem 2.40
[Difficulty: 2]
Given:
Velocity distribution between flat plates
Find:
Shear stress on upper plate; Sketch stress distribution
Solution:
Basic equation
du
yx =
dy
yx =
At the upper surface
Hence
y=
du
=
dy
d
dy
u max 1
2
2 y = u 4 2 y = 8
Problem 6.44
[Difficulty: 2]
Given:
Wind tunnel with inlet section
Find:
Dynamic and static pressures on centerline; compare with Speed of air at two locations
Solution:
Basic equations
p dyn =
1
2
2
air U
p
air =
Rair T
p 0 = p s + p dyn
p = w g h
p atm
Problem 1
With a Biot number of hL/k = (250 W/m2K 0.05m)/48 W/mK = 0.260, a lumped
capacitance analysis should not be performed. At any time during heating, the lowest
temperature in the slab is at the midplane
o =
To T ( 550 800 ) C
=
= 0.417 = C1
HW5
Problem1:
The initial rate of heat transfer from a plate is
q = 2hAs (Ti T ) = 2hL2 (Ti T )
With ReL=uL/=10m/s1m/30.410-6m2/s=3.29105, flow is laminar over the entire surface
and
1/3
NuL = 0.664 Re1/2
= 0.664(3.29 105 )1/
Problem 1:
a) q = kS T
q=
T
Rt
S = 1/ kRt
Using the thermal resistance relations, their corresponding shape factors are:
Plane wall:
Rt =
L
kA
S=
A
L
Cylindrical shell:
Rt =
ln(r2 / r1 )
2 Lk
S=
2 L
ln r2 / r1
Spherical shell:
Rt =
1 1 1
Heat Transfer - ME 116A
HW5
1. Steel plates of thickness =6mm and length L-1m on a side are conveyed from a heat treatment
process and are concurrently cooled by atmospheric air of velocity u=10m/s and T=20 i
Heat and Mass Transfer
ME 116A - HW4
1. Annealing is a process by which steel is reheated and then cooled to make it less brittle. Consider the
reheat stage for a 100-mm-thick steel plate (=7830kg/m3, c=550J/kgK, k=48 W/mK), which is initi
Heat and Mass Transfer
ME 116A
HW1
1. The composite wall of an oven consists of three materials, two of which are of known
thermal conductivity, kA=20W/mK and kC=50W/mK, and known thickness, LA=0.3m and
LC=0.15m. The third material, B, which
Heat and Mass Transfer
ME 116A
HW2
1. Consider one-dimensional steady state conduction in a plane composite wall. The
outer surfaces are exposed to a fluid at 25 and a convection heat transfer
coefficient of 10
Heat and Mass Transfer
ME 116A
HW3
1. Using the thermal resistance relations, determine shape factor expressions for:
a. plane wall, cylindrical shell, and spherical shell.
b. Isothermal sphere of diameter D at
Problem1
From an energy balance on wall B,
! B A = 0
q1 A q2 A + 2qL
q! B = ( q1 + q2 ) / 2LB
To determine the heat fluxes, q1 and q2 , construct thermal circuits for A and C:
q1 = (T1 T ) / (1/ h + LA / k A )
q1 = 2
Problem 4.38
[Difficulty: 2]
Given:
Data on flow at inlet and outlet of a reducing elbow
Find:
Find the maximum velcoity at section 1
Solution:
r
r
V dA = 0
Basic equation
CS
Assumptions: 1) Steady flow 2) Incompressible flow
Evaluating at 1, 2 and 3
h
_§OL U 77 Q n/
MgllM
Quiz #2 27-2012 _ 120 points totai
;.
First and second name
Student ID number
Probiem 1 (30 points): Draw the pressure distribution on the submerged surfaces below. (Draw the net
pressure on the surface = P P am) Problem 2 (90
ME113FluidMechanics
Final
3202011
100pointstotal+20 extra
Firstandsecondname
StudentIDnumber
ClosedbookClosednotesIllegibleanswerswillbemarke dasincorrect
Problem 1 (25 points): A 4m long quarter circular gate of ra dius 3m and of negligible weight is h
ME113FluidMechanics
Final
3152011
100pointstotal
Firstandsecondname
StudentIDnumber
ClosedbookClosednotesIllegibleanswerswillbemarke dasincorrect
Problem 1 (25 points): A 4m long quarter circular gate of ra dius 3m and of negligible weight is hinged
abo
Navier-Stokes Equations
In cylindrical coordinates, (r, , z), the continuity equation for an incompressible fluid is
1
uz
1
(rur ) +
(u ) +
=0
r r
r
z
In cylindrical coordinates, (r, , z), the Navier-Stokes equations of motion for an incompressible flu
Problem 8.86
Given:
Data on flow through Alaskan pipeline
Find:
[Difficulty: 2]
Head loss
Solution:
Basic equation
2
2
p
p
h
V1
V2
lT
1
2
+
+ z1
+
+ z2 =
= HlT
g
g
2 g
2 g
g
oil
oil
Assumptions: 1) Steady flow 2) Incompressible flow 3) at 1 an