Harmonic excitation of the boundary layer.

[Conceptual]

Is it possible to harmonically excite the boundary layer to reduce boundary layer buildup?

I found these while searching for something else:

http://www.sfxtechnologies.com/products.html

If these were mounted to the inside of the bodyparts, could they realistically be used to vibrate at a certain frequency to increase laminar boundary conditions?

Would it be considered a "movable aero device"? Could it be used undetectably during scruitineering?

Thoughts?

[Giblet]

Interesting. I'm sure this effect must take place naturally around at least the engine cover. No way taht giant soundboard doesn't vibrate at certain times.

Make certain parts to resonate at certain engine notes/speeds to have it happen naturally when and where you want it.

It could be done passively or actively with a device not far removed from speakers and tone generators.

[Conceptual]

It could be used for cancellation as well...

But would it improve boundary layer conditions?

[Giblet]

I am unedumicated.

I can only look at causes or effects, and make no correlation between them

[timbo]

The was a pdf called "Ferrari technical innovation" that circulated over the web and there was a paragraph on just that. Although as far as I can recall acoustic waves were used to excite microvortices that would help to control the wake car produces and reduce drag.

[BreezyRacer]

I would rather think we're likely to see surface textures, which are totally legal and test-able, as well as easily done via CNC equipment. It's an interesting idea to try to vibrate a surface to break down boundary layers but I presume it would take a considerable amount of energy to vibrate CF panels, as well as taxing the adhesive used to position these things, and lastly, find room to place them.

[Conceptual]

I would rather think we're likely to see surface textures, which are totally legal and test-able, as well as easily done via CNC equipment. It's an interesting idea to try to vibrate a surface to break down boundary layers but I presume it would take a considerable amount of energy to vibrate CF panels, as well as taxing the adhesive used to position these things, and lastly, find room to place them.

If you read about them, you will see that 99% of your argument is simply untrue.

I don't think that texturizing static molds would be easier or more tunable than the vibration transducers, as they will not change at given speeds and yaw angles, not to mention chassis harmonics due to the engine. Also, driving them is not a problem, as once again, if you actually look at the site that I linked, there are very lightweight and small amplifiers that would be able to do the job.

My question is: Can vibrating bodypanels thin out a thickened boundary layer?

[kilcoo316]

My question is: Can vibrating bodypanels thin out a thickened boundary layer?

Why bother?


Look folks. Form drag is absolutely negigible on a Formula 1 car.


Forget about boundary layer flows, unless it is separation on the suction surface of a wing, in which case you will want a turbulent boundary layer...



(and yes, if you get the vibrations right, you theoretically could interfere with the formation of Tollmien-Schlichting waves which are central to boundary layer transistion from laminar to turbulent)

[Scotracer]

My question is: Can vibrating bodypanels thin out a thickened boundary layer?

Why bother?


Look folks. Form drag is absolutely negigible on a Formula 1 car.


Forget about boundary layer flows, unless it is separation on the suction surface of a wing, in which case you will want a turbulent boundary layer...

Don't you mean skin drag is negigible?

[kilcoo316]

Don't you mean skin drag is negigible?

Apologies, I'm incorrectly applying the term as it would be defined on (subsonic) aircraft.


There, form drag is composed of direct skin friction and pressure drag from BL growth.



Of course, in an F1 car, separating form drag from induced drag is much harder. But with the open wheeled nature of an F1 car, of course the basic form drag will be painfully high even without the presence of wings.



What I should have said was skin friction drag and pressure drag caused by boundary layer displacement is negligible on an F1 car.

[Conceptual]

What about using harmonic excitation on the underbody panels or diffusor?

[Scotracer]

Don't you mean skin drag is negigible?

Apologies, I'm incorrectly applying the term as it would be defined on (subsonic) aircraft.


There, form drag is composed of direct skin friction and pressure drag from BL growth.



Of course, in an F1 car, separating form drag from induced drag is much harder. But with the open wheeled nature of an F1 car, of course the basic form drag will be painfully high even without the presence of wings.



What I should have said was skin friction drag and pressure drag caused by boundary layer displacement is negligible on an F1 car.

There we go.

Incidentally I'm going to uni again to do an MSc in Aerospace Engineering.

[kilcoo316]

What about using harmonic excitation on the underbody panels or diffusor?

Why?

Again, you don't particularly want laminar boundary layers on an F1 car... in fact, you'd be best trying to avoid them!

[kilcoo316]

Incidentally I'm going to uni again to do an MSc in Aerospace Engineering.

In...?


If its software based - try to go open sourced. Oh, and try to get onto every and any training program you can get hold of! (But, if you've been out of academia, you'll probably know that and understand why too)


Means you can come out, go specialised contracting after and not have to worry about licence fees.

[Scotracer]

Incidentally I'm going to uni again to do an MSc in Aerospace Engineering.

In...?


If its software based - try to go open sourced.


Means you can come out, go specialised contracting after and not have to worry about licence fees.

The Uni has wind tunnels but a lot of the course is CFD-based. I know there's a lot to choose from on that front. And I'm doing it at Glasgow University.