n2omike wrote: ↑Mon May 20, 2019 10:03 pm
SchmidtMotorWorks wrote: ↑Mon May 20, 2019 9:39 pm
If gravity did play a factor in this it seems that air would flow into the upper duct and out the lower duct (i think we can agree it doesn't)
The ONLY role gravity plays, is its part in providing the pressure differential.
It doesn't matter if the carbs are updraft, downdraft or sidedraft. Makes ZERO difference. The pressure differential is the same.
The buoyancy example was to show that gravity alone is not providing a NET force on the air column in any given direction.
Gravity's sole role is it's part in providing the pressure differential.
Im no physics expert so imagination is at work here! I understand gravity's role in providing the pressure differential, so yeah no matter which way up the tunnel ram is, if you have a depression at one end , air will flow in the other end in an attempt to equalize the depression with the outside pressure(atmosphere).
Of course in an intake the air flow is not in one continuous direction or at a steady speed so gravity must play 'some' role on any incompletely vaporized fuel (liquid droplet) because if the depression were only slight and the tunnel ram was upside down(as in an updraft) and the airflow was not fast enough moving for it to carry the fuel droplet with the air , the fuel droplet would be subject to gravity and drop out of the air flowing upward. At some point in airspeed the fuel droplet will then equalize with gravity and (of course until it vaporizes) would 'hover' due to gravity pulling the droplet down and air speed pulling/holding the droplet up. Then increase the airspeed again and the droplet will begin to move in the direction of airflow.
Whereas the same scenario but with the tunnel ram in a down draft position, that droplet is going to fall with gravity down the runner no matter the air speed but will fall if course faster as the air speed increases.
This is probably a little off the actual subject but I would love to see Jon Kaase's clear intake test done in an up draft position, some of the fuel that is washing around and not really going anywhere 'looks' as though more than just air flow is affecting it.
https://youtu.be/7Iq1B-2paCs
Probably way off track again but and putting other forces at play, in a downdraft manifold/pipe scenario, keeping in mind that air has mass and is compressable, what would happen to the moving air column that is flowing toward a depression if we could suddenly accelerate the entire manifold, toward/inline with gravity and up to the same speed as the moving air colum?
Then same scenario BUT away from gravity,,, then in an updraft situation same again , , with and away from gravity?
From all that waffle I still dont know the answer but am having fun thinking about it!
Craig.