Originally Posted by
heliman500
@Vessbot Thanks for your input. The video is a great representation of the Coriolis effect, however, it really doesn't focus on the law in question; conservation of angular momentum.
Coriolis Effect and conservation of angular momentum are absolutely different! Stating that Coriolis effect is the same as conservation of angular momentum is like saying distance is the same as speed in the old speed, distance, time formula.
It is important to remember that two different physical principles are involved when defining Coriolis 'force', namely, conservation of absolute angular momentum and centrifugal accelerations felt in the rotating frame.
Coriolis effect is reserved for describing the fictitious deflection of a moving object in an a non-inertial rotating frame of reference. It is nothing more than a method to quantify the magnitude of the fictitious force. However, in the case of a rotor system there is nothing 'fictitious' about a rotor rpm speed change, it is actually happening. This phenomena is the direct result of conservation of angular momentum. The formula that defines the rpm change:L=R x MV
where R =radius, m =Mass, V = linear velocity
Well it seems we're in complete agreement on why the coning-in rotor speeds up, but disagree on the nomenclature. L = rmv, L and m are each conserved, therefore r and v are inverse. It leads to an actual RPM change. So far, we're together. But you use the presence or absence of this actual RPM change, as the discriminator of whether the conservation of angular momentum is what's happening. Well in the inward sprinkler experiment, the RPM of the water droplets also
actually changes, so it meets your own standard. Then why do you say the video doesn't "focus" on this law?
Yes conservation of angular momentum and Coriolis aren't exactly the same thing, but the latter is merely an example of an effect, directly caused, by the former.
If the water droplet was somehow attached to the tube, then their diverging motions through this attachment would create a force, and through it the forward-accelerating droplet would pull the tube forward. How, then, would the setup be different from a coning in rotor or figure skater? (This was described in the rotating frame. In the outside frame, the droplet moves in a straight line, but the section of tube that it's closest to, moves backward. Same relative motion, caused by the same difference in the physical world: straightline-moving droplet, decreasing-radius along the tube.)
So, with or without the genius Mr. Coriolis' calculation of the apparent deviation, the blade rpm change is going to happen. Why not call it what it actually is?
I'm OK with calling it other things, but I take exception to that calling it an example of Coriolis is incorrect, or that it and the conservation of angular momentum are "absolutely different."