Coriolis force

[swansont]

I always thought pantheory's explanation was the right one Ophiolite.

Typhoons and hurricanes rotate in opposite directions in northern and southern hemispheres, just like your sink or toilet bowl, due to Coriolis effects ( radial movement in a rotating frame of reference ), hence the different nomenclature.

Do you have a reference, I'd really like to know if its just an east/west thing?

 

Your sink or toilet bowl do not rotate as a result of the Coriolis force. It's waaaaay to weak to cause the rotation (the earth only rotates 2*pi per day, after all). It's trivial to make the water flow in the opposite direction. (demonstrated by accident when a shyster was filmed doing this and got the rotation direction wrong)

[Airbrush]

Your sink or toilet bowl do not rotate as a result of the Coriolis force. It's waaaaay to weak to cause the rotation (the earth only rotates 2*pi per day, after all). It's trivial to make the water flow in the opposite direction. (demonstrated by accident when a shyster was filmed doing this and got the rotation direction wrong)

Are you saying that water does NOT spiral down a drain in opposite directions in northern and southern hemispheres?

[MigL]

Well since we are off topic...

At my place of employment we use parallel tube coriolis flow meters, and the deflection of the tubes is definitely not trivial swansont. It is of large enough magnitude to make these meters among the more reliable and accurate flow meters available.

 

But what does this have to do with typhoons and galaxies ?

[swansont]

Are you saying that water does NOT spiral down a drain in opposite directions in northern and southern hemispheres?

 

It can, it's just not due to the coriolis force.

Well since we are off topic...

At my place of employment we use parallel tube coriolis flow meters, and the deflection of the tubes is definitely not trivial swansont. It is of large enough magnitude to make these meters among the more reliable and accurate flow meters available.

 

Do these devices use the coriolis force of the earth's rotation? I somehow doubt that.

 

edit: according to what I could find on the net, these meters use the conservation of angular momentum of the fluid within the device. Completely separate issue.

[studiot]

It should be pointed out that the magnitude of the Coriolis force or effect depends upon size of the moving system or range of movement.

 

That is why it is (sometimes) significant in the path of winds and ocean current.

[hoola]

coriolis force is not responsible for the toilet in my north american home running CCW? That is remarkable. I do have a question related to the phenomena, regardless of cause. If I were on the exact equator and flushed a toilet, which way would it rotate? Would there be a rotation sometimes CW, sometimes CCW, sometimes straight down, with no rotation? I would think straight down......edd

Edited December 23, 2013 by hoola

[John Cuthber]

Are you saying that water does NOT spiral down a drain in opposite directions in northern and southern hemispheres?

If it does then the equator runs through the bathroom of the house I used to live in because the sink and bath drained with opposite spirals.

 

Is it more credible that

1 some other force is involved or

2 the equator runs through the North of England?

 

 

If there were no other forces involved and if the bath was big enough then the Coriolis effect would make a difference.

There are and it isn't so it doesn't.

[J.C.MacSwell]

You have the angular momentum of the water in the bowl, any further angular momentum introduced by the flush or shape of the bowl, and the usually insignificant coriolis effect all coming into play

[swansont]

coriolis force is not responsible for the toilet in my north american home running CCW? That is remarkable. I do have a question related to the phenomena, regardless of cause. If I were on the exact equator and flushed a toilet, which way would it rotate? Would there be a rotation sometimes CW, sometimes CCW, sometimes straight down, with no rotation? I would think straight down......edd

Run the numbers. I mean, this is a science site, right?

 

At the north or south pole, the Coriolis force can be responsible for the maximum effect of 1 rotation per day. Conservation of angular momentum means that as the fluid drains and the vortex becomes smaller, it will speed up. If R drops by a factor of 2, it will be a whopping 2 rotations per day. Another factor of 2 and it will be 4 rotations per day. (and alll of this drops off with the sine of the latitude)

 

Tell me, does that describe the effect you see in your toilet?

 

Toilets rotate the way the jets in the rim dictate they will rotate. Basins drain based on irregularities in shape and any residual angular momentum the water has from how it was filled.

[hoola]

So another urban legend is getting sick, but not quite dead.....edd

actually my toilet has an interesting flush pattern. The normal CCW overall vortex begins upon flushing, but as the flush continues, the body of water get a swollen area that manifests itself as rather substantial and begins to bob up and down in a rather interesting fashion. It is an old school 5 gal flush, which I picked up at a salvage yard when I needed a new toilet as I don't like the new 1.6 gal ones...I have never seen this pattern in a toilet flush before, as I pay attention to such things, it being uniquely patterned and very consistent. My cat loves to watch the water swirl and and then slop side to side in an oscillatory fashion. I propose a test for all persons coming to this thread, using a standard 5 gal toilet, since they have no active elements to skew the swirl pattern, and give a CW or CCW report and include whether they live in the upper or lower hemisphere...maybe someone in equador with a house straddling the equator will offer an answer to my original query.....I am on the side of the coriolis effect as the "initilizer" of the preferred direction of rotation. Unless toilets sold in respective hemispheres have a built-in bias with an angle to the jets of one way or another, of which I seriously doubt, than the coriolis effect actively affecting toilets legend lives on.....edd

[cosinus]

I found an interesting article about Coriolis effect : http://www.adilca.com/coriolis-force.pdf

"to make the Coriolis effect appear significantly the sink should be covering several square kilometres" !

So the effect of Coriolis force in an ordinary-sized sink is completely negligible !