Electroaerodynamic drag reduction...

[Cycle]

I've been reading up on this, and supposedly they've achieved drag reductions of up to 96% at supersonic speeds, but only about 10% at subsonic speeds. Still, a 10% reduction in drag is pretty good, especially at only 20 watts total power expended (at 38,500 volts), as I saw in one subsonic study.

My thinking is to inject a high voltage plasma out front of the vehicle, with the opposing electrode at the rear of the vehicle. That'd do two things... it'd force the stalled air further forward, essentially creating a low-pressure void into which the vehicle moves, and it'll help to reattach the air flow near the rear of the vehicle as the charged air seeks the opposite polarity electrode. That leaves a smaller wake, thus you get drag reduction.

Has anyone tried this?

[Frank Lee]

Yeah, but all the flashing from bug zapping proved to be too great a distraction.

[freebeard]

I've been reading up on this...as I saw in one subsonic study.

That's helpful. Link?

Is it like the anti-gravity stuff on the B-2 bomber?

[redneck]

.

Interesting.

http://laboratorios.fi.uba.ar/lfd/we...-et-al_old.pdf




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[Cycle]

Originally Posted by freebeard

That's helpful. Link?

Is it like the anti-gravity stuff on the B-2 bomber?

I've read through so many of them, I'm unsure if this is the exact one I referenced, but it's pretty easy to Google for any number of studies, just search for "aerodynamic drag reduction by energy deposition", "subsonic aerodynamic drag reduction by energy deposition" and similar variations:

Brown.edu Research Projects (PDF)
"The energy was deposited instantaneously along a finite length of the cone axis, ahead of the cone's bow shock, causing a cylindrical shockwave to push air outward from the line of deposition. The shockwave would sweep the air out from in front of the cone, leaving behind a low-density column/tube of air, through which the cone (vehicle) propagated with significantly reduced drag. The greatest drag reduction observed was 96% (100% drag reduction would result in the complete elimination of drag forces on the cone). The propulsive gain was consistently positive, meaning that the energy saved due to drag reduction was consistently greater than the amount of energy "invested" (i.e. deposited ahead of the vehicle). The highest ratio of energy-saved/energy-invested was approximately 6500% (a 65-fold "return" on the invested energy)."

Here's another good one:
Nonequilibrium Plasma Aerodynamics (PDF)
"Promising applications of plasma systems to control flow involve management of laminar-to-turbulent transition in the boundary layer, the management of flow detachment or attachment to the surface, and the resultant management of lift and drag force of an airfoil.

The authors [Mhitaryan et al, 1961, 1964] demonstrated up to 30% drag force decrease and 40% lift force increase for airfoil with 460 mm chord length (AoA = 8 degrees), thickness of 13% and flap length 30% (AoA = 43 degrees) of the chord in velocity range from 8.75 to 20.4 m/s."

[freebeard]

demonstrated up to 30% drag force decrease and 40% lift force increase for airfoil

Bingo!

Instead of being an anti-gravity force, this effect has been found to be caused by ionized particles exerting a force between two asymmetrical electrodes that produces a type of ion drift or ionic wind that transfers its momentum to surrounding neutral particles, an electrokinetic phenomena or more widely referred to as electrohydrodynamics (EHD).
...
There are claims that all major aerospace companies in the 1950s including Martin, Convair, Lear, Sperry, Raytheon were working on it, that the technology became highly classified in the early 1960s, that it is used to power the B-2 bomber, and that it can be used to generate "free energy".

https://en.wikipedia.org/wiki/Electrogravitics

more discussion at https://en.wikipedia.org/wiki/Biefel...93Brown_effect

The Biefeld–Brown effect is an electrical effect that produces an ionic wind that transfers its momentum to surrounding neutral particles. The effect was named by inventor Thomas Townsend Brown who claimed that he did a series of experiments with professor of astronomy Paul Alfred Biefeld, a former teacher of Brown who Brown claimed was his mentor and co-experimenter at Denison University in Ohio. The phenomenon was also given the name "electrogravitics" by Brown based on his belief this was an electricity/gravity phenomenon. The effect is more widely referred to as electrohydrodynamics (EHD) or sometimes electro-fluid-dynamics, a counterpart to the well-known magnetohydrodynamics.

[aerohead]

Originally Posted by Cycle

I've been reading up on this, and supposedly they've achieved drag reductions of up to 93% at supersonic speeds, but only about 10% at subsonic speeds. Still, a 10% reduction in drag is pretty good, especially at only 20 watts total power expended (at 38,500 volts), as I saw in one subsonic study.

My thinking is to inject a high voltage plasma out front of the vehicle, with the opposing electrode at the rear of the vehicle. That'd do two things... it'd force the stalled air further forward, essentially creating a low-pressure void into which the vehicle moves, and it'll help to reattach the air flow near the rear of the vehicle as the charged air seeks the opposite polarity electrode. That leaves a smaller wake, thus you get drag reduction.

Has anyone tried this?

According to NASA,the sub-sonic base drag of a supersonic aircraft can be 80% of it's overall aerodynamic drag,with 20% surface friction drag.Ionizing the air would be targeting this 20% of drag.
Using conventional streamlining techniques,this 80% of drag can be eliminated on an automobile,leaving 7-12% surface friction drag.
Ionizing this 7-12% might yield only a 3 1/2-6% loss due to air friction,yielding a 1 3/4-3% mpg increase using gross reasoning.
1950's ionizing research was abandoned owing to inefficiencies in ionizing power requirements.Sounds like they've made a breakthrough in electronics.

[freebeard]

If air is effectively incompressible then Viktor Shauberger's biological submarine could also work in air.

[aerohead]

Originally Posted by freebeard

If air is effectively incompressible then Viktor Shauberger's biological submarine could also work in air.

Looks like it would.Might not be real efficient.The inlet is wrong,and the air into the impeller might need some curves,as well as the jets.
I'd be looking at modern high-bypass turbofans.

[freebeard]

The engineering is rudimentary. Maybe he was dumb-ing it down for his times. His inspiration was realizing trout can keep station in a moving stream of water by gulping water through their gills. They flick their tail when they want to go somewhere.