# AOE 4064

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1. The table lists values of
Reynolds number for various animals in motion.

For which cases is the inertia of
the fluid important?

a. whale @ 10 m/s: Re=300,000,000

b. flying duck @ 20 m/s:
Re=300,000

c. dragonfly @ 7 m/s: Re=30,000

d. larva @ 1 mm/s: Re=0.3

e. bacterium @ 0.01 mm/s:
Re=0.00003
2. A radio antenna on a car consists
of a circular cylinder 1/4 inch in diameter

and 4 feet long. The bending
moment at the base of the antenna when the

car is going 55 mph is about:
3. The wind in a storm reaches a
speed of 65 mph blowing perpendicular

against a 3 ft X 6 ft window in
the side of a high-rise building with

dimensions much larger than the
window. 65 mph is the wind speed at the

height of the window. The force
4. A 1:10 scale model of a whale is
to be tested in a towing tank or water

tunnel at a speed such that the
Reynolds number in the test matches that in

the real situation. In that case,
the drag force for the model test and the real

situation can be expected to
compare as
5. A fish whose length is twice its
maximum diameter resembles a spheroid

and has a specific gravity of
1.2. If added mass is ignored, the percentage

error in a calculation of its
acceleration from rest would be about:
6. A 2 cm. diameter cylinder is in a
4 m/s air stream. The frequency of vortex

shedding would be expected to be
7. The boundary layer thickness at
the end of a 4.0 m. long plate in an air

stream of 5.0 m/s would be about:
8. A chemical called NTA that is
frequently used in detergents leaks into a

small lake with a surface area of
0.2 square km. and a maximum depth of

9.0 m. The vertical profile of
NTA concentration, C in micromoles per cubic

meter vs. z in meters, is
measured as listed below:

z: 1.0, 2.0, 3.0, 4.0, 5.0, 6.0,
7.0, 8.0, 9.0, 10.0

C: 5.2, 5.1, 4.9, 3.2, 2.9, 2.6,
2.4, 2.1, 1.8

If the vertical turbulent
diffusion coefficient is 1.2 cm**2/s, the vertical flux

of NTA in
moles/m**2/s at a depth of 7.0 m. is about:
9. At high Reynolds number, the
power needed to overcome the drag of a body

moving at a speed, U, varies as U
to the power n, where n equals about:
10. A fluid has a viscosity of 0.001
lb-sec/ft**2 and a specific gravity of

0.913. At a location on a solid
surface where the edge velocity is 45 in/sec,

there is a laminar boundary layer
3.0 inches thick. Assuming a linear

velocity profile, the shear in
the middle of the boundary layer is:
11. True/False

It is possible for the drag on a
tall, slender tree trunk to be the same in a 2.0

mph wind as in a 4.0 mph wind.
12. True/False

There is an important effect of
altitude on the drag of small pollen particles

under conditions where the
temperature change with altitude is negligible.
13. True/False

The Reynolds number for a flowing
glacier is large
14. True/False

Useful locations for wind energy
generation occur uniformly across the

USA.
15. True/False

Wind-generated waves and Tsunamis
move at very different speeds
16. True/False

The Froude number is proportional
to the ratio of viscous forces to gravity

forces.
17. True/False

Internal waves do not occur in
the ocean.
18. True/False

One can calculate the vorticity
in a boundary layer without knowing if the

flow is laminar or turbulent.
19. True/False

Murray's Law is an early example
of multidisciplinary design optimization.
20. True/False

The pressure drop for turbulent
flows in very rough pipes does not vary

with Reynolds number
21. True/False

The Stokes Radius refers to the
distance of detection of surface insects by

fish.
22. True/False

The production of thrust by
creatures in the Low Reynolds number regime

does not depend upon circulation.
23. True/False

The wingbeat frequency of insects
decreases with insect size.
24. True/False

The "clap and
fling" mechanism is important to understanding insect flight.
25. True/False

strongly with body shape.
26. True/False

Some creatures derive a
significant proportion of their total lift from their

body.
27. True/False

The drag of creatures in the low
Reynolds number regime varies as their

speed squared.
28. True/False

Atmospheric boundary layer flows
can be studied in conventional wind

tunnels without substantial
modifications.
29. True/False

Fick's Law is used to model mass
transport and diffusion in nature.
30. True/False

Temperature effects can be
neglected in the modeling of chemical and

biological reactions in nature.

### Card Set Information

 Author: kylecaro ID: 127636 Filename: AOE 4064 Updated: 2012-01-13 20:23:09 Tags: Fluids Folders: Description: Previous exam questions Show Answers:

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