Fluid Mechanics Experiment #1: Flow Velocity Measurement


[MUSIC PLAYING] Hello everyone. Welcome to
our first experiment in fluid mechanics. In this experiment, you will learn two things.
One, the basic operation of the 15 ton amphere wind tunnel. Two, you will learn how to measure
flow velocity. In this particular case, that’s the wind velocity by three different devices–
turbine anemometer, pitot static tube with water manometer, hardware anemometer. Let’s first install those three devices into
the working area of the wind tunnel. Let’s install the turbine anemometer first. Remove
this little cover. Remove the cover for the turbine anemometer. Slide this one through
the foam cover. Mount this one to the working area. Remember to lock the device. Now the
turbine anemometer has been installed in the working area. Next, let’s install the pitot static tube.
Remove the middle cover. Carefully align the direction of the tube in the direction of
the airflow. Lock the device. The pitot static tube has two plastic tubes
labeled as 11 and 12. 11 will give you the reading of the static pressure. You need to
connect at the 11 tube to the port 11. This is the port 11. Push this one harder into
the port. When you hear the click, which means the device is locked. That’s it. Then number 12. 12 will give you the reading
of total pressure. Push this one into port 12. When you hear the click, it means the
device is locked. That’s it. So now the pitot static tube has been connected
to the water manometer. 11 will be connected to the water tube 11. 12 will be connected
to the water tube 12. When we have different velocity, those two water levels in those
two tubes will be different. Later, we will be able to use some formula to convert the
[? head ?] difference into the velocity reading. This is the pitot tube with water manometer. Then we need to install the hardware anemometer.
Carefully remove the red cover. Remove the cover on top. Use the small plastic tube to
help with the installation. You need to be very careful. You need to align the hot well
in the direction of the airflow. Lock the device. Now all three devices– hardware
anemometer, pitot static tube with the water manometer, and the turbine anemometer all
have been installed in the working area of the wind tunnel. Next, we’re going to power on the wind tunnel.
Switch up to supply the power to the wind tunnel. Then come to the computer. The computer
has installed software with hardware with the wind tunnel, and the communications all
have been connected. You just need to log into your account. And [INAUDIBLE]. There’s
an icon in the middle of the desktop. Create [INAUDIBLE] this one. You will see a list
of exercise. We pick up the first one, exercise A. Click
on load. You will see a little window like this. Then you need to change the ambient
temperature of 18 degrees Celsius to the room temperature to 23 degree Celsius here. The
software will use this temperature value to do the [INAUDIBLE] to get those physical properties
of the airflow. When you say the watchdog [? enabled ?] small grain little LED illuminator,
which means the wind tunnel and the software– everything is ready to use. We need to click on the file [? one. ?] You
will see the number zero over here. You click on the one, this number will automatically
change to one. It means the wind tunnel now it’s ready to use. And you can increase the
wind tunnel velocity by change the numbers of fan speed from zero to 20%. You will see
the noise started. That’s the fan turn on. And also please remember, this 20%– it’s
not the velocity of 20 meters per second. It gives you the 20% percent of the potential
of the fan velocity. So now we need to turn on the hardware anemometer.
Push the On button on the hardware anemometer. The hardware anemometer will first do a self-diagnose.
When the self-diagnose is finished, it will give you the reading of meters per second
directly. Then we need to turn on the turbine anemometer. Push it on bottom. And we also
need one of the group member to stand on the other side of the wind tunnel to keep reading
the velocity from the turbine anemometer. And you also need to recall the water level
in tube 11 and the tube 12. The difference between those two water level will give you
the reading of the velocity. You will have to do this calculation later by some formula. This is 20% of potential. When the steps finish,
increase the potential to 25%. Wait about 60 seconds to let the airflow become stable.
When the airflow becomes stable, record the data one more time, again, from hardware anemometer,
turbine anemometer, water level in tube 11 and tube 12. And also record the data from the software,
which give you the direct reading of velocity. In this particular case, seven meters per
second. This is for 25%. When this step finish, increase the velocity
potential to 30%. Wait for another 60 seconds. When the airflow becomes stable, record the
data, as the previous step. Then increase this to 35%. Keep doing this– repeat the
procedure like this until you reach 100%. This is 100%. When 100% is finished, gradually slow down
the wind velocity by changing the potential to 50%, then 20%, then 0%. This will complete
this experiment. That’s it.

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