h a l f b a k e r yPoof of concept
add, search, annotate, link, view, overview, recent, by name, random
news, help, about, links, report a problem
browse anonymously,
or get an account
and write.
register,
|
|
|
Jim reckons maglev is expensive - and might be the reason people
used horse drawn boats running in water filled canals instead…
He also figures the physics have not changed.
Jim proposes a magnetic field strong enough to attract a thin layer of
saline to the surface of a train. The said vehicle
can then be drawn
along an empty ((edit) not dry) canal as if it was water filled.
Sneaky…
how to do it
http://en.m.wikiped...agnetohydrodynamics
belive it or not [madness, Oct 22 2011]
Please log in.
If you're not logged in,
you can see what this page
looks like, but you will
not be able to add anything.
Annotation:
|
| |
Po check out the link (feel free to delete your comment) because
I am about to… |
|
| |
Max has a horrible feeling that the viscous drag on
the train will be far greater than the rolling friction
of wheels. He also thinks that this idea is
evolutionarily convergent with a slug. |
|
| |
He does, however, think it's ingenious. If he can
ever meet this Jim chap face to face, he would give
him a bun. |
|
| |
Too complicated; why use magnetohydrodynamics (yes, I
believe it, as does anyone else who has ever A) wondered
if Tom Clancy was full of $#!+ or B) seen or read about
that Japanese MHD-drive boat) when the train could just
as easily work by simple capillary action? |
|
| |
Is Jim is not capable of posting his own ideas? |
|
| |
Or is Jim being set up as a scapegoat? |
|
| |
Slow-moving boats are great, because water has no limiting friction, but drag increases with the square of velocity. And with a thin layer of liquid, and massive shearing forces, drag is going to be substantial. |
|
| |
The train won't float, as such; its weight is not counteracted by buoyancy due to displacement. Instead, the liquid is acting as a lubricant. So why not use a ferrofluid, or an oil ? |
|
| |
Maintaining ride height and stability will be ... challenging. |
|
| |
Jim needs to make sure he takes his meds regularly. |
|
| |
What [Master Quest] said. |
|
| |
As others have said, this would not work to float a vehicle, the best you could hope for is a hydrodynamic lubrication, but that only works by letting some of the fluid trail of the back. You could then use magnetohydrodynamics to pull thr fluid around to the front. |
|
| |
At that point, however, you will find it far more effecient to simply put wheels on the vehicle. |
|
| |
Saline solution was presented because it is a natually occuring organic compound. I agree that there is likely to be a better inorganic compound. |
|
| |
//This would mean carrying a large supply of saline in on-board tanks, and at that point you've lost all chance of gaining any efficiency. |
|
| |
Not really --- the fluid supporting the train can be gathered from the water way itself. Only a small amount of saline needs to be present, just sufficient to 'wet' the surface. |
|
| |
//the best you could hope for is a hydrodynamic lubrication, but that only works by letting some of the fluid trail of the back. |
|
| |
Again not really --- the amount of fluid trailing out the back will be small and constantly replenished. |
|
| |
//At that point, however, you will find it far more effecient to simply put wheels on the vehicle. |
|
| |
I think the analogue here is that of an ice skate. Which is to all intensive purposes frictionless. The pressure of the skate on the ice melts/creates a tiny bead of water which will trail behind the skater. |
|
| |
Here, energy is required to gather and maintain such a bead of water under the train. The amount of energy required is small compared to that required to levitate. Which is why ice skates and this idea work so well... |
|
| |