Help with a project - Air speed, compressed?

In summary, the conversation discusses the relationship between wind speed and compression in a wind tunnel. The participants discuss using a ratio of the areas of the openings to estimate the wind speed without an anemometer, and the point at which compression becomes an issue. They also mention the equation of continuity and the equation for density, and how to use them to solve for the output velocity. Finally, the conversation explores ways to increase the output speed, such as enclosing the airflow from the fan.
  • #1
bpears
10
0
1.If you have a wind tunnel, a tubing that goes from a large opening, to a smaller opening, with the larger opening facing the wind, will the wind speed be more out the smaller end since its being compressed?

2.Is there a way to calculate/guesstimate the difference in wind speed by the volume or something (you know, a way without a anemometer or something?)

For the sake of explanation: let's say the large opening is 3 times larger than the smaller opposite end. And that the wind speed is 20mph. (Or what ever you prefer for a good example.)
 
Physics news on Phys.org
  • #2
Or would that not make compression?
 
  • #3
Welcome to PF!

At that low speed, there will be no compression. You can simply ratio the areas of the openings.
 
  • #4
So if it were 30mph in, and the ratio was 1:10, then it would be 300mph out?

What speed into tube, would cause compression, and then would the compression make the output speed more than the size in/out ratio?
 
  • #5
At about 220mph input or output, compression starts to be an issue.
 
  • #6
Well, I actually want compression if it will increase the wind speed out the other end. So would that change the equation with compression? And did I give a correct example of the ratio you describe?

Thanks for your help, I've been looking all over online for something about this, but couldn't find anything.
 
  • #7
Ok, so I see what you're saying kind of now. I found the equation of continuity.
But are you supposed to square the ratio before multiplying to the input speed?

Here's the equation I have:
V1A1=V2A2.

But I think that is for no change in density? Is change in density meaning compression?

For density, I found this:
p1V1A1=p2V2A2.

I'm having trouble understanding how to use the equations to solve for the other velocity, if someone could work out an example? Or would I just multiply by the ratio like Russ was saying (output size ratio 1:10, 30mph in=300mph out?)?
 
Last edited:
  • #8
Your example is using a tube open at both ends, so the air in the larger tube is nearly stopped (not flowing at 30 mph), due to the restriction at the transition into the smaller tube.
 
Last edited:
  • #9
How could I have a higher output speed?
 
  • #10
bpears said:
How could I have a higher output speed?
You would need to enclose the air flow from the fan, such as a blow dryer or a leaf blower.
 

FAQ: Help with a project - Air speed, compressed?

What is air speed and why is it important in a compressed project?

Air speed refers to the velocity at which air molecules are moving. In a compressed project, air speed is important because it affects the amount of air being compressed and can impact the efficiency and effectiveness of the project.

How is air speed measured in a compressed project?

Air speed can be measured using instruments such as an anemometer or a pitot tube. These devices can measure the speed and direction of air flow and provide accurate readings for a compressed project.

What factors can affect air speed in a compressed project?

There are several factors that can affect air speed in a compressed project, including the size and shape of the compressed air system, the temperature and humidity of the air, and the amount of resistance or obstacles in the air flow.

How can air speed be increased in a compressed project?

To increase air speed in a compressed project, the size and shape of the compressed air system can be optimized for efficient air flow, obstacles can be minimized or removed, and the temperature and humidity can be controlled to create ideal conditions for air compression.

What are the safety considerations when working with high air speeds in a compressed project?

Working with high air speeds in a compressed project can be dangerous, so it is important to follow safety protocols and use proper protective equipment. This includes wearing ear protection to reduce noise levels, using safety goggles to protect against debris, and following proper handling procedures for compressed air equipment.

Similar threads

Pressure required for air flow through nozzle
Replies
1
Views
2K
Gas Usage in Cars: Effects on Environment
Replies
29
Views
3K
Compression of air entrained in water
Replies
4
Views
2K
I Drag equation - relative flow velocity
Replies
11
Views
2K
Pressure calculation for compressible gas and variable 'g'
Replies
6
Views
2K
Flow of air through an open tube with a balloon
Replies
9
Views
3K
Wind speed calculation from a pressure setting
Replies
2
Views
2K
I Work Done/Energy Transferred in One Dimensional Collision
Replies
5
Views
1K
Questions About the Atmospheres of Various Sizes of Artificial Planets
Replies
0
Views
2K
Engineering How Does Cup Anemometer Design Utilize Fluid Mechanics Principles?
Replies
4
Views
2K

Hot Threads

Recent Insights

Back
Top