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BadBrain
BadBrain is offline
#4
Oct23-11, 02:02 AM
P: 197

Centrifugal pump question.


Quote Quote by Low-Q View Post
I do not think the Coriolis effect have anything to do with those planes. Their initial velocity on the ground is the same (as the earth rotation at that point), so the land masses will too. The planes will not be affected by the rotation of the earth.

My claim is precisely that air travel along a due east-west axis will involve no coriolis forces, as there's no change in the distance of the plane from the center of the rotating body (earth). That's why I questioned the intelligence of the guy on the other forum who suggested it.

Assuming a perfectly calm day (i.e., the air is moving at the same velocity as the Earth), the plane flying from Tehran will have benefit of the fact that the Earth's rotation is bringing Tel Aviv closer to him, whereas the plane flying from Tel Aviv to Tehran will experience the opposite effect. Even artillery shells, which travel far shorter distances than airplanes, must have the Earth's rotation accounted for by their gun's guidance system if they are to hit their targets.

EDIT: CORRECTION:

You're partly right! Under the conditions I described, earth's rotation would be cancelled out by a headwind hindering the first plane and a tailwind assisting the second plane, if they were both flying at haircut altitude. But most modern air combat operations are conducted at far higher altitudes, where the thinner air will exert less dynamic pressure against the speeding aircraft than will the thicker air on deck. Thus, the effect I mentioned will be observed.

Quote Quote by Low-Q View Post
Well, back to the centrifugal pump experiment:

I just tried with a LOOONG tube with a 90 degree bend at the end - in air. I held the tube in my hand, and spun myself around, and so the tube.
However, on my side of the tube I attached a plastic bag (wrapped around the tube end) that was filled with air - as much air a plastic bag can carry with an open end.
When the 90 degree bend pointet towards rotation, the air did not escape from the bag - the bag did not deflate or inflate.
When I aligned the bend towards the floor or ceiling, it took about 4 rounds (1/2 round pr second) to deflate the bag.
When I pointed the bend away from rotation, the bag deflated in only 2.5 rounds (1/2 round pr. second) to deflate the bag.

I repeated the experiments many times - spinning in both directions untill I got sick...

The average result is what I explained above.

PS! Yes I removed the TV set, the speakers, my wifes many flowers and "stuff", and the kids, before the experiment

Vidar
Once again, great experiment! You're working out all of the corollaries of your theories. You're doing a thorough job. I like that.