What is the safest blockage ratio?

[Donny]

Hello!

Anyone can help me to find the best blockage ratio between for a small ball in tube? so the pressure can stay up (not drop).
How to calculate it.

Thank You.

 

[Donny]

Anyone?

Could somebody please point me how to get it? ebook, website, etc?

 

[ank_gl]

pressure ll always drop if there is a restriction in the pipe, you need to be more specific. can you show any diagram?

 

[Donny]

I want to calculate what is the safest ratio for blockage ratio.
Here is the diagram.

As you can see, the ball is in the middle of the tube. The ball has blockage ratio which is Area of ball:Area of tube
I want to compare my blockage ratio with the standard blockage ratio for wind tunnel.