MAE 300 Hw3
Problem 1
Drag force is produced by a flow around an object. To relate the forces involved with the object, Reynolds number was introduced. The Reynolds number of an object relates the inertial forces to the viscous forces of the fluid to the object interaction. In Experimental testing, a pitot static tube is typically
used to determine flow velocity which can be used to generate velocity profiles. Determine the Uncertainty of using a Pitot static tube for finding the Reynolds number.
Velocity
: V
=
√
P
t
−
P
s
ρ
, Where P
t
is the total pressure, P
s is the static pressure and ρ is the density. A manometer reads in P
t
-P
s
.
The formula for Reynolds number is ℜ=
VL
v
Where V is velocity, L is some length parameter and ν
is the Kinematic viscosity. Use the following values to solve the Uncertainty
P
t
-P
s
= 10.74 +/- 0.02 Pa, ρ = 101.3 +/- 0.05 Kg/m^3, ν
= 15.11*10
-6
+/- 0.3*10
-7
m^2/2 and L = 10 +/- 0.01
cm
Problem 2
Find Uncertainty for the equation below
R
=
a
5
b
2 3
√
c
√
d
Problem 3
A set of data was collected and is used to calculate the final non-dimensional parameter. In the data there was found to have a bias and precision error as seen in the table below. Find the value and its uncertainty.
Parameter
True Value
Measured Value
Precision error
N data collected for Precision error
W
1.25
1.29
0.02
10
X
4.23
4.23
0.50
10
Y
10.59
11.00
0.34
10
Z
15.11
15.33
0.23
10
C
s
=
X
3
√
Y
W
2
Z
