# Liquid filled toriod

joe shmo
Science 02 Nov '15 01:16
1. joe shmo
Strange Egg
02 Nov '15 01:161 edit
My coffee maker use little toroids filled with liquid creamer. When I flip the creamer disk (like you would flip a coin) the creamer cup changes its axis of rotation...how are the dynamics of the liquid generating the net torque to accomplish this?
2. DeepThought
02 Nov '15 01:44
Originally posted by joe shmo
My coffee maker use little toroids filled with liquid creamer. When I flip the creamer disk (like you would flip a coin) the creamer cup changes its axis of rotation...what is generating the net torque to accomplish this?
I'm not sure I get the set up, how is this different to the effect with, for example, a gyroscope where there is an effect at right angles to the applied torque and axis of rotation?
3. joe shmo
Strange Egg
02 Nov '15 02:53
Originally posted by DeepThought
I'm not sure I get the set up, how is this different to the effect with, for example, a gyroscope where there is an effect at right angles to the applied torque and axis of rotation?
Imagine a puck lying flat on a table, put the origin of the standard three dimensional coordinates system through its centroid or CM. I induce a rotation about the "x" axis. The end result is the rotation is still about the "x" axis, but the puck has reoriented it self such that there is a combined 90 degree rotation about the "x" axis and a 90 degree rotation about the "z" axis. The rate at which this occurs also "appears" to have some dependency on the initial angular velocity of the puck. This does not happen with a solid puck, just one with liquid in it...This is different from gyroscopic procession of a top, right?
4. DeepThought
02 Nov '15 04:52
Originally posted by joe shmo
Imagine a puck lying flat on a table, put the origin of the standard three dimensional coordinates system through its centroid or CM. I induce a rotation about the "x" axis. The end result is the rotation is still about the "x" axis, but the puck has reoriented it self such that there is a combined 90 degree rotation about the "x" axis and a 90 degree rota ...[text shortened]... puck, just one with liquid in it...This is different from gyroscopic procession of a top, right?
Is the direction of the additional rotation consistent, or does it always turn the one way?
5. joe shmo
Strange Egg
02 Nov '15 12:43
Originally posted by DeepThought
Is the direction of the additional rotation consistent, or does it always turn the one way?
The direction of the compound rotation may or may not be consistent, I can't tell. One face is printed, I've only observed it stabilizing in two orientations, the one I described above, and 180 degrees from it. Another observation: it always appears to stabilize at or around the apex of the trajectory.
6. DeepThought
02 Nov '15 18:45
Originally posted by joe shmo
The direction of the compound rotation may or may not be consistent, I can't tell. One face is printed, I've only observed it stabilizing in two orientations, the one I described above, and 180 degrees from it. Another observation: it always appears to stabilize at or around the apex of the trajectory.
The only things I can think of is random design variation in the donut thing and effects from trapped air bubbles. There are two ways a bubble could plausibly influence it. When the thing is tipped up the air bubble moves up in the tube so fluid moves the other way. This would produce a net rotation of fluid in the tube at right angles to the tipping so we'd expect the effect. The plus with this explanation is that it would explain variation in the direction of turning, as that would depend on which side the bubble is moving. The problem with it is that I really wouldn't expect the effect from the displacement of an air bubble to be big enough to do it.

The alternative is simply that the air bubble makes the thing slightly heavier on one side so the torque you apply isn't quite around the axis you think it is. I'm not happy with this explanation because I'd still expect it to be too small an effect.

So the basic problem with bubble based explanations is that I find it difficult to believe the effect would be noticeable. Are you sure this isn't a feature of the surface of the toroidal cream holder thing. I'm imagining a donut type thing made by sticking two halves together with the join around the outside edge, so that if you rolled it along the join would be along the point of contact with whatever surface it is rolling on. If the join sticks out at all it might provide the explanation to this rather than anything to do with movements of the fluid in the torus.
7. sonhouse
Fast and Curious
03 Nov '15 17:24
Originally posted by joe shmo
My coffee maker use little toroids filled with liquid creamer. When I flip the creamer disk (like you would flip a coin) the creamer cup changes its axis of rotation...how are the dynamics of the liquid generating the net torque to accomplish this?
Is it possible for you to make a little youtube video of the device?