Home Work:
due Aug. 10
th
at the beginning of class – no late HW accepted
1
(a) What is the likelihood that a flow with of water in an industrial quality
pipe of diameter 0.010 m to be laminar or turbulent, when the average
velocity is 1 m/s and the kinematic viscosity is 10
6
m
2
/s?
(b) Is it possible
for this flow to be different than what you answered in a?
2
Please compare the velocity profile (sketch), the wall shear stress (
τ
w
=
μ
du/dy
wall
),
and the pressure drop per unit length for laminar and turbulent
flow at the same Re number.
3
A given pipe first carries water and then air at 15
o
C and atmospheric pressure. What
is the ration of the mass discharge rates, if the friction factor, f, were the same for both
flows.
f = (dp/dx)D/( ½
ρ
U
avg
2
). Hint for a give pipe there is a unique friction
factor/Reynolds number relationship. So if the friction factor is the same for both
flows, so is the Re number.
μ
air
= 1.8 x 10
5
Ns/m
2
;
μ
water
= 1.155 x 10
3
Ns/m
2
4
Given:
A 100 meter high tree with veins of radius 20 x 10
6
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview.
Sign up
to
access the rest of the document.
 Summer '09
 Rohr
 Fluid Dynamics, Darcy, friction factor, Darcy friction factor

Click to edit the document details