View Single Post
Old 12-16-2011, 06:36 PM   #511
bambbrose
Wiring Nerd
 
bambbrose's Avatar
 
Join Date: Nov 2011
Drives: 1994 Supra
Location: Wake County NC
Posts: 455
Thanks: 17
Thanked 19 Times in 12 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by Dimman View Post
Question regarding some language in that book.

In the context of exhaust gas velocity and this formula:

Gas Speed = Piston Speed X (D^2 / d^2)

D= dia of bore
d= dia of port


This is under the condition of "When the coefficient of flow is unity."

What does that mean "coefficient of flow is unity"?

Is it something to do with pressure differentials or something?
I believe "unity" in this case means constant. Unity can be defined as "unvaried", and therefore can be said to be constant.

I'm sure for the formula to work, you have to hold the coefficient constant, otherwise there are too many unknowns.

Coefficent of flow = fluid friction, or "the resistance to flow", in layman terms.
bambbrose is offline   Reply With Quote