SE115 HW 6 Answer
1. Step # 1 List all the variables and find k
= (, , , , ) , k = 6
Step # 2 Express each variable in terms of basic dimensions
= 2 1 = = = 2 = F4 2
So: r = 3 (F, L, T)
= F2
Step # 3 Determine the required number of Pi terms
Pi theore

University of California, San Diego
Department of Structural Engineering
SE 130B Spring 2015
STRUCTURAL ANALYSIS II
Homework 2,
DUE April 13, 2015 6 PM
Problem 1
The structure shown in composed of rigid carts connected by spring with DOFS (us)
indicated.

SE110B Assignment 1
Due 04/10/2015
1. A wire is used to hang a lantern over a pool. Neglect the weight of the wire, and
assume that it is taut, but strain free, before the lantern is hung. When the lantern
is hung, it causes a 50-mm sag in the wire. Deter

SE115 Assignment 2
Due 01/22/2010
1. For the inclined-tube manometer of the following figure the pressure in pipe A is
0.8 psi. The fluid in both pipes A and B is water, and the gage fluid in the
manometer has a specific gravity of 2.6. What is the pressu

SE115 Assignment 6
Due 02/20/2015
1. Water flows over a dam as illustrated in the following figure. Assume the flow rate, q,
per unit length along the dam depends on the head, H, width, b, acceleration of
gravity, g, fluid density, , and fluid viscosity,

SE115. Lecture 12 (Monday, 01/30/2016)
Chapter 5. Control Volume Analysis
5.1 The Reynolds Transport Theorem
B=mb, b is properties per unit mass
e.g. B=mass if b=1, B=kinetic energy if b=V2/2
B=momentum if b=V
CV = Control Volume (fixed)
SYS = system of f

SE115. Lecture 11 (Friday, 01/27/2017)
Chapter 4. Elementary Fluid Dynamics - The Bernoulli Equation
4.2 F=ma normal to a streamline
V2
Fn = m an = R
Fn = Wn + Fpn
p
= cos
n
cos = dz / dn
dz p V 2
=
dn n
R
Integrate over n
V2
dn + z = const
p +
R
4.

SE115. Lecture 15 (Friday, 02/03/2017)
5.4 Conservation of energy
Time rate of increase of the total energy of the system =
Net time rate of energy addition by heat transfer into the system +
Net time rate of energy addition by work transfer into the syst

SE115. Lecture 6 (Wednesday, 01/18/2017)
2.4 Hydrostatic force on a plane surface
FR = pdA = hdA = y sin dA
A
A
A
FR = sin ydA = sin yc A
A
1
ydA
A A
Acting point of FR
yc =
FR y R = ydF = sin y 2 dA
A
A
2
y dA
Ix
, I x is the 2nd moment of inertia
yc A
y

SE115. Lecture 7 (Friday, 01/20/2017)
2.7 Buoyancy
FB =
Chapter 3. Fluid Kinematics
3.1 Description of a flow: Eulerian vs. Lagragian descriptions
Material/Substantial Derivative: D/Dt
Df f
=
+ v f
Dt t
3.2 Useful terms for flow description
Streamline:

SE115. Lecture 2 (Wednesday, 01/11/2017)
Chapter 1. Introduction
1.1 Basic characters of fluids
Fluids and solids
Similarities
The continuum hypothesis is used for both fluids and solids.
The fundamental laws of mechanics apply to both fluids and solids.

SE115. Lecture 4 (Friday, 01/03/2017)
2.2 Basic equation of the pressure field
Surface force (due to pressure) in y direction:
p y
p y
xz p +
xz
Fy = p
y 2
y 2
p
xyz
y
Similarly,
p
p
Fx = xyz , Fz = xyz
x
z
In vector form:
v
Fs = Fxi + Fy j + Fz k
=

SE115 Assignment 8 answer
1. At x=3 m, Rex = 1.5 10 6 , = 5
* = x
=x
1.721
Rex
0.664
x
U
= 0.00422 m,
= 0.00163 m
Rex
w = 0.332U 3 / 2
x
= 0.0678 N/m2
2.
c=
g
= 2.79 m/s
2
q2
3. E = y +
= 1.204 m
2 gy 2
4.
= 0.0122 m,

1. We create a control volume that includes the fluid inside the engine. Let the force
on this control volume to be F.
(a) By using the conservation of mass equation, we have
2
2
2
V1 2 D D
D
2
V1 +
= V D
43
2 4 3
4 3
4
18
V1 = V
5
(b) By using the

L9 The pressure difference. Ap. across a partial blackagc
in an artery (cal-led a stenosio‘) is approximmnd by the equation
2
Ap = Ku—D— + K"(—l'— l)pV2
where v is the blood velocity, o me blood viscosity (FL—2T),
p the blood density (541:3), D the artery

SE115 Assignment 8
Due 03/13/2015
1. A smooth flat plate of length l = 6 m is placed in water ( = 1000 kg/m3,
= 10 6 m2/s) with an upstream velocity of U = 0.5 m/s. Use the Blasius solution
and determine the boundary layer thickness, the displacement thi

SE110B Assignment 3
Due 04/25/2014
1. The aluminum-alloy shaft AC (G=20 GPa) has an 800-mm-long solid segment
AB and a 400-mm-long tubular segment BC. The shaft is subjected to the
torsional loading shown in the following figure. The diameters are:
d 1 =

SE115 Assignment 7
Due 03/06/2015
1. To cool a given room it is necessary to supply 4 ft3/s of air through an 8-in.diameter pipe. Approximately how long is the entrance length in this pipe?
2. A soft drink with the properties of 15 0C water is sucked thro

SE115 Assignment 5
Due 02/13/2015
1. Air flows past an object in a 2-m-diameter pipe and exits as a free jet as shown in
the following figure. In the input the velocity is 10 m/s and uniform. In the output
the velocity is nonuniform as indicated. The pres

SE115 Assignment 4
Due 02/06/2015
1. Air flows steadily through the contraction shown in the following figure. Derive
an expression for the fluid velocity at (2) in terms of D1 , D2 , , m , and h.
2. The wind blows through a 7 10 -ft garage door with a sp

SE115 Assignment 3
Due 01/30/2015
1. An underwater vehicle moves with velocity ui w k through water. The salinity of
water changes as T ( x , y , z , t ) = az cos(bt ) . Find the rate of change of temperature
measured by the probe.
2. (a) In a rescue oper

SE115 Assignment 2
Due 01/23/2015
1. A mercury manometer is connected to a large reservoir of water as shown in the
following figure. The specific gravity of mercury is 13.6. Determine the ratio
hw / hm .
2. For the inclined-tube manometer in the followin

SE115 Assignment 1
Due 01/16/2015
1. The volume rate of flow, Q, through a pipe containing a slowly moving liquid is
R 4 p
given by the equation Q =
, where R is the pipe radius, p the pressure
8l
drop along the pipe, the dynamic viscosity, and l the leng

1. With the Couette flow profile, the shear stress on the bottom of the mass is
= x& / h . Therefore the total shear force on the mass is A = x&A / h . According to
Then b = A / h .
2.
h
. In the y-coordinate, the centroid of the gate is
2 sin
h
h
3h
+

SE115. Lecture 3 (Wednesday, 01/11/2017)
1.5 Viscosity
Dynamic viscosity & kinematic viscosity
Chapter 2. Fluid Statics
2.1 Relation of pressure w.r.t. the orientation of the plane it acts on
Balance of force in y:
F
y
= p yxz psxs sin =
xyz
2
ay
Balance

SE115 HW 6 Answer
Q
11.46 ft/s. Density = 2.38 10 3 slug/ft3
1
D 2
4
Dynamic viscosity = 3.74 10 7 lb.s/ft2
Reynolds number: Re = VD / = 48,614
Therefore the flow is turbulent
le
1/ 6
= 4.4(Re ) , l e = 17.7 ft
D
1. Average speed in the pipe V =
Density