# Frictionless Fluid

I wanted to know if it is possible for a fluid to have negative friction ’ that is if its possible for a fluid to be frictionless
I dont personaly think its impossible but the implications of this kind of natural Phenomenon would certainly be far reaching

Apparently this theory (As the title suggests) is purely theoretical
And as i dont have the time to web surf for the next 12 years in search of the answer ’ i was hopeing you could

And if this theory was proven correct ’ what are the general implications regarding
Well . . . . . Whatever it would effect?

One word : superfluidity

The term ‘negative friction’ would tend to suggest something that acts in such a way as to accelerate something, rather than slowing it down or allowing it to continue to move unimpeded at the same velocity - which would require an energy input.

A potentially close match to what you’re looking for might be superfluids - Superfluidity - Wikipedia

I think what you’re looking for is a fluid with zero viscosity, which is a property of a superfluid. Viscosity is a measure of how well a fluid will transmit shear stress perpendicular to the flow, or how strongly it will “pull along” adjacent fluid. So viscosity is analagous to friction.

You’re not going to find any substance with negative viscosity. As Mangetout said, negative viscosity implies the spontaneous acceleration of fluid, which is an energy gain.

For the same reason, you can’t have a negative friction coefficient between solid surfaces: this would imply you could step onto “negative friction ice” and it would accelerate you across the pond.

To have negative viscosity, you’d have to have a situation analogous to that of a laser, where the fluid has some of its atoms in an excited state, able to drop into a lower energy state, to provide the energy for the accelerating fluid.

I have never heard of such a thing, but it’s at least potentially possible.

… also known as the Toyota Effect.

I was going to say something similar.

If you put a superfluid in a bucket, and slowly started the bucket rotating, the superfluid will stay stationary. However, there might be some perturbation one could make that would briefly couple the superfluid with the spinning bucket. The superfluid would then gain more angular momentum than imparted by the perturbation (gaining some from the bucket as well)–effectively giving the interaction a “negative” viscosity.

How interesing . . . . . . .

I just wanted to put the resulting fluid into a water gun

But this has raised my left eyebrow

Can a superfluid be stirred?

Then use one of these guns;).

No, shaken.

Thats a very good question.

Well played sir.

(but the question remains - if you’ve got a tumbler full of superfluid that has no viscosity and is frictionless, what happens if you put a spoon or paddle in there and start moving it about?

I think it’s going to fly out of the bucket and hit the jet on the conveyor belt.

Inviscid flow, which is something of a circular definition, but a standard fluid dynamics simplification.

Remember the fluid still has mass, even if it doesn’t have viscosity, and the free surface and walls of your tumbler affect any flow.

I would imagine it would create a supernova inside of a black hole for no reason yesterday tomorow right now