[MUSIC PLAYING]
Good morning everyone.
Welcome to your fluid mechanics
experiment number two.
In this experiment, you
will measure the pressure
distribution around a
cylinder in the crossflow.
In order to do this
experiment, you
need a wind tunnel,
the water manometer,
and of course, the
specially designed cylinder.
We will mount the
cylinder in this way,
and then the airflow will
be in this direction.
This specially designed cylinder
has 10 holes on the surface.
Each hole will be
connected individually
to a tube like this.
And each tube will be later
individually connected
to the water manometer.
So when we mount the
cylinder into the working
area of the wind tunnel, hole
number one will be horizontal.
So we'll I actually measure
the pressure distribution
at the zero degree angle.
Hole number two, we'll be
able to measure the pressure
distribution at a
20 degree angle.
Hole number three, we'll be
able to measure the pressure
distribution at 60 degree angle.
So that's how we measure
the pressure distribution
over the surface.
Now we need to mount the
cylinder to the wind tunnel.
Remember to align the pin with
the support on the other side
of the wind tunnel.
Also remember you need to align
those two markers to make sure
that hole number one
will the zero degrees,
which is the
horizontal direction.
Lock the two wires.
Then we need to
connect the cylinder
to the water manometer with the
quick release 10-way connector.
It has to make a good
contact, and lock the device.
Now the cylinder
is ready to use.
We now can power on the
wind tunnel, then come
to the computer, click on
the icon on the desktop,
and pick up [INAUDIBLE],
and click on Load.
You will see a pop
up window like this.
First thing we need to do is
change the temperature value
from 18 degree to 25 degree.
This is the temperature
in this lab.
And you also noticed
that watch dog enabled
has been illuminated,
which means now
the connection between
the wind tunnel
and the software on the
computer has been built.
So we will be able to start to
use the wind tunnel right now.
So we can start the fan.
You click the fan on, the number
will be automatically changed
from 0 to 1.
Now we can increase the fan
speed from zero potential
to 20% percent of potential.
You will see the
fan's not running.
Wait for about 60 seconds to
let the air flow become stable.
Then you can start collecting
your first set of data.
Your first set of
data will include
the velocity of
the air flow, which
provided from the
software right now,
is about 6.5 meters per second.
Then you need to come
to the water manometer
to record the data
in the water tubes.
Be careful that when you read
the water level in the water
manometer, you have to
bend down like this.
Make sure your sight is
perpendicular to the water
panel, so you get
high accuracy rate.
So this will be your
first set of data.
Then you can increase
the fan speed to 30%.
Again, you have to wait
for another 60 seconds
to let the air
flow become stable.
Then you can start collecting
your second set of data, which
includes the air
velocity right now is
about 8.8 meters per second.
And also you need to come over
here to the water manometer
to read the water
levels in the tubes.
After this, you can increase
the fan speed to 40%.
Every time, remember you
have to wait for 60 seconds
to let the air
flow become stable.
Then you can collect the data.
So 40% will be your
third set of data.
Which includes the air
velocity right now is
about 11.1 meters per second.
And again, you need to
come to the water manometer
to read the water level in
the water manometer carefully.
Repeat the same steps
until you reach 100%.
Remember for 100%, you also
need to wait for 60 seconds,
then collect your
last set of data.
Then gradually slow
down the wind tunnel,
and this will be your second
experiment in fluid mechanics.
