Dielectric-barrier discharge (DBD) for drag reduction

[Logic]

I was looking into research on using Dielectric-barrier discharge (DBD) to minimize or eliminate the reverse flow in fan shrouds/ducts caused by wing/blade tip vortex shedding. When I came across this:
Aerodynamic drag reduction for a truck model using DBD plasma actuators
https://journals.sagepub.com/doi/10....78132221087852

"...the maximum drag reduction using three comb-shaped plasma actuators at the trailing edge of the trailer is 8.7%..."

I imagine that this may just be the tip of the iceburgon 'aero-ing' the rear of cars without using long tails. Maybe not, but certainly worth more research.

Speaking of research:
Sci-hub
is your friend. (Google it. Try more than just the 1st result as ScienceDirect and other research paper peddlers are forever trying to shut them down)
NB that you also get browser extensions to automate the process, but buyer beware...

Oops; wrong place and no way to delete the post..?

[freebeard]

Oops; wrong place and no way to delete the post..?

Petition the mods.

I imagine that this may just be the tip of the iceburgon 'aero-ing' the rear of cars without using long tails. Maybe not, but certainly worth more research.

The best old thread seems to be ecomodder.com/forum/showthread.php/plasma-drag-reduction from 2016-04.

[Logic]

This makes more sense to me vs AC:
https://www.nature.com/articles/s41598-019-42284-w

See Fig 4, 5b and 6 to get the visual summary.

Thx for the link Freebeard.

Mod/s plz could you move this.

[freebeard]

Mod/s plz could you move this.

Try a Personal Message. There's a Contact Us link in each page footer.

[aerohead]

Originally Posted by Logic

I was looking into research on using Dielectric-barrier discharge (DBD) to minimize or eliminate the reverse flow in fan shrouds/ducts caused by wing/blade tip vortex shedding. When I came across this:
Aerodynamic drag reduction for a truck model using DBD plasma actuators
https://journals.sagepub.com/doi/10....78132221087852

"...the maximum drag reduction using three comb-shaped plasma actuators at the trailing edge of the trailer is 8.7%..."

I imagine that this may just be the tip of the iceburgon 'aero-ing' the rear of cars without using long tails. Maybe not, but certainly worth more research.

Speaking of research:
Sci-hub
is your friend. (Google it. Try more than just the 1st result as ScienceDirect and other research paper peddlers are forever trying to shut them down)
NB that you also get browser extensions to automate the process, but buyer beware...

Oops; wrong place and no way to delete the post..?

Here's the tip-off that the investigators reside completely within an academic environment, and don't yet know a thing about fluid mechanics / aerodynamics, their results having no bearing on the 'real world.'
' Trust no one '

[Logic]

Originally Posted by aerohead

Here's the tip-off that the investigators reside completely within an academic environment, and don't yet know a thing about fluid mechanics / aerodynamics, their results having no bearing on the 'real world.'
' Trust no one '

The "tip off"?
Where?

As far as I could see they did an OK job of their experiment..?

Then the 2nd link really got my attention as the electron flow is in one direction vs AC DBDs.

DBD Plasma Actuation on the Blades of Axial-Flow Turbomachinery

Abstract

Flow separation, or stall, in axial flow turbomachinery results in a loss of pressure or compression in the case of fans and compressors, or the loss of power or thrust generation in the case of turbines. Wave-power-based Wells turbines, in particular, suffer so acutely from blade stall during normal operation, that it compromises their viability as a major renewable energy resource. In this research, pulsed dielectric barrier discharge (DBD) plasma actuators were implemented on the blades of a mono-plane Wells turbine impeller and its full-bandwidth performance was evaluated. An initial parametric study indicated that blade-tip reduced frequencies ≥2.5 produced the greatest impeller acceleration from rest. The corresponding physical pulsation frequency was then used as a basis for conducting nominally steady-state experiments as well as experiments involving acceleration and deceleration of the impeller. Data so acquired, corresponding to a reduced frequency range of 0.9 to 2.5, was compiled to construct an impeller performance map. Plasma pulsations dramatically increased the effective impeller bandwidth by producing useful net power well beyond flow ratios where mono-plane impellers spin down to a standstill. In fact, the shaft power at a 17° blade-tip angle of attack exceeded the plasma input power by a factor of 33. These findings are potentially game-changing for wave energy generation and axial flow turbomachinery in general.

https://link.springer.com/chapter/10...030-90727-3_16

A factor of 33 at an angle of attack of 17 degrees..!
How does this stuff not get your interest?
17 degrees with no stall/turbulence means a way shorter tail for a vehicle.

One might also encourage a air direction change on the high pressure area of a vehicle's nose.

[freebeard]

The "tip off"?
Where?

drag reduction ... is 8.7%?

I appreciated the mention of the Wells turbine, but then they go on about angle of attack.

Wells turbine
The Wells turbine is a low-pressure air turbine that rotates continuously in one direction independent of the direction of the air flow. Its blades feature a symmetrical airfoil with its plane of symmetry in the plane of rotation and perpendicular to the air stream. Wikipedia

[aerohead]

Originally Posted by Logic

The "tip off"?
Where?

As far as I could see they did an OK job of their experiment..?

Then the 2nd link really got my attention as the electron flow is in one direction vs AC DBDs.

DBD Plasma Actuation on the Blades of Axial-Flow Turbomachinery

Abstract

Flow separation, or stall, in axial flow turbomachinery results in a loss of pressure or compression in the case of fans and compressors, or the loss of power or thrust generation in the case of turbines. Wave-power-based Wells turbines, in particular, suffer so acutely from blade stall during normal operation, that it compromises their viability as a major renewable energy resource. In this research, pulsed dielectric barrier discharge (DBD) plasma actuators were implemented on the blades of a mono-plane Wells turbine impeller and its full-bandwidth performance was evaluated. An initial parametric study indicated that blade-tip reduced frequencies ≥2.5 produced the greatest impeller acceleration from rest. The corresponding physical pulsation frequency was then used as a basis for conducting nominally steady-state experiments as well as experiments involving acceleration and deceleration of the impeller. Data so acquired, corresponding to a reduced frequency range of 0.9 to 2.5, was compiled to construct an impeller performance map. Plasma pulsations dramatically increased the effective impeller bandwidth by producing useful net power well beyond flow ratios where mono-plane impellers spin down to a standstill. In fact, the shaft power at a 17° blade-tip angle of attack exceeded the plasma input power by a factor of 33. These findings are potentially game-changing for wave energy generation and axial flow turbomachinery in general.

https://link.springer.com/chapter/10...030-90727-3_16

A factor of 33 at an angle of attack of 17 degrees..!
How does this stuff not get your interest?
17 degrees with no stall/turbulence means a way shorter tail for a vehicle.

One might also encourage a air direction change on the high pressure area of a vehicle's nose.

1) Aerodynamic drag is closely associated with 'Boundary-Layer-Theory.'
2) The very fact that the investigators reported the Reynolds number that they did belies the fact that they haven't a clue about aerodynamics or fluid mechanics.
3) Their findings are 'trash'.
4) It won't prevent them from achieving a Ph.D. though, as people who are completely 'wrong' about physics can get Ph.D.s any day of the week!

[Logic]

https://www.youtube.com/watch?v=-v67vVTGgIs

NB how the air is NOT staying laminar over this stalled wing at a high angle of attack.
Then tell me how it's simply NOT going to keep flow attached on a short/er boat tail because I don't have Reynolds' number!

Lets NB that an electron traveling at around 175 000km/h (IIRC) does not stop until it's inside the 2nd surface.
Any air molecule that may have been ionized by said electrons may well be traveling a lot slower, but also does not stop until IT is the molecule on the opposite charged surface.
ie: Airspeed is of little importance here and Boundary Layer is no longer part of the equation!

For anyone else who doesn't give a buck afout Renaults or his nucking fumber after seeing that,
See B here for how you do DBD:

in this paper here:
https://www.nature.com/articles/s41598-019-42284-w

Here are all the high voltage doodats you might require:
https://ioninjection.ponderworthy.com/articles/parts

[freebeard]

https://en.wikipedia.org/wiki/No-slip_condition

At the boundary between the fluid and a solid surface, the attraction between the fluid molecules and the surface atoms is strong enough to slow the bulk velocity to zero. Consequently, the bulk velocity of the fluid decreases from its value away from the wall to zero at the wall.

IMHO opinion (I don't have the time to read your links ) the plasma creates a virtual surface with a non-zero velocity for the bulk flow to adhere to.