AirTabs shown to work by respected EM member

[freebeard]

Suppose a freewheeling or slightly draggy pinwheel on a stalk just downstream of the point where a vortex springs up. Would the pinwheel absorb energy from the vortex and dissipate it? Would the added drag eat any savings for lunch?

[Xist]

Originally Posted by freebeard

Suppose a freewheeling or slightly draggy pinwheel on a stalk just downstream of the point where a vortex springs up. Would the pinwheel absorb energy from the vortex and dissipate it? Would the added drag eat any savings for lunch?

I doubt this helps at all, but here is footage of a pinwheel in a wind tunnel. Starting at 19 seconds: Toyota Windtunnel - Pinwheel on Vimeo

[freebeard]

That was cute, it even had the little o_0 guy in the corner.

It answers the question. In my thought experiment, I added a strain gauge at the base of the stalk. Since I'm back in the thread I think I'll watch the video in #59 again.

[ChazInMT]

Ya know what grabbed my attention in FreeBeards video thing, the computing power required to squiggle the smoke rings and make the pretty designs.

It took 4,096 CPU's working together to simulate the flow.........

To me this means any kind of computer flow calculations regarding flow around a vehicle, airplane, tree, garden gnome, or anything else is suspect. A single parameter in the computer programming being out by a fraction of a percent is compounded 4,096 times. Computers may be a good tool to rough in aerodynamic stuff, but can't be relied upon for real world performance. The complex interactions of fluid around a moving body are truly mind boggling and extend out many yards from the surface of the object in question, so even tuft testing really only provides a miniscule insight on the total picture since it is looking at what is going on in the 1st 1/2" or so of the air movement.

Testing results from wind tunnels and careful ABA testing, to me, are the ways we can have faith in what represents reality.

[freebeard]

I like the idea of a wind tunnel/water flume that has barn-door sized paddlewheels instead of propellers. If you move air/water in big blobs instead of thrashing it with a fast moving propeller there would be less turbulence.

And florescent green smoke/bubbles.

As for the 4K CPUs—if they were quad core you only need 1024.

I believe newer chips ship with up to 16 cores. ...and 4K Von Neumann CPUs would about equal one qubit-based quantum processor. They exist in the labs.

The best video I've found since re-viewing that last one is

Extraordinary Toroidal Vortices

[ConnClark]

Originally Posted by freebeard

I like the idea of a wind tunnel/water flume that has barn-door sized paddlewheels instead of propellers. If you move air/water in big blobs instead of thrashing it with a fast moving propeller there would be less turbulence.

ummm paddle wheels are not efficient due to the vortices they create.

Its also of note that any wind tunnel worth its salt will have the propellers distanced far enough away from the test area that any vortices generated will have been disipated by the time they get there or will have been passed through a flow straightener.

[freebeard]

I was inclined toward articulated paddles that would slide sideways as they release the air, so I could see that. But I can let that idea go as easily as I picked it up.

...any wind tunnel worth its salt will have the propellers distanced far enough away from the test area that any vortices generated...

So propellers do create turbulence too. I thought paddlewheels fell out of favor because of their size compared to propellers.

[ConnClark]

Originally Posted by freebeard

I thought paddlewheels fell out of favor because of their size compared to propellers.

There are many reasons paddle wheels fell out of favor... efficiency, size, weight, cost, vulnerability to large waves, how waves effect the steering with them, etc....

They still do make some boats with them however. They can't be beat for a boat that requires a very shallow draft and a boat that is very likely to run aground.

[NachtRitter]

What do you get when you combine wind tunnel propellers and shallow draft boats ?

[freebeard]

ConnClark -- Those are all problems that wouldn't translate into the water flume, though; right?

If the two paddlewheels met tip-to-tip would they have less turbulence than if they were out of phase?