Soundwaves Boost Wing Lift

On Sat, 20 Aug 2005 16:31:43 -0700, wrote
(in article . com):

Here's some news that recently came out:

http://www.newscientist.com/article.ns?id=dn7867

http://abc.net.au/science/news/stories/s1439827.htm

Apparently, soundwaves can help airflow stay near the wing and increase
lift. This can help smaller aircraft to avoid stalling at lower
airspeeds. Is this a technology that could be usefully applied to
existing small aircraft? Or would it require some totally new design
thinking?


I have some of the piezo polymer film they were probably using (from SONAR
experiments, and a steel plate target that tells you where the bullet hit).
The amplitudes would be very small, but covering a wing on an RV or Bonanza
would be less than five pounds in weight, including the high voltage
electrics needed for the piezoelectric material.

But New Scientist is not the most reputable source (called New Age Scientist
by some, ignored by the rest) and I would have to see this confirmed by
another lab. It smells a lot like the kind of signal that screws up your
instrumentation. The drive for the film is likely 800 to 1,200 volts and at
400 Hz running on a little model in a wind tunnel with sensitive detectors of
various sorts. I'll just say I'm skeptical.

-- Charlie Springer

Charlie Springer wrote:
On Sat, 20 Aug 2005 16:31:43 -0700, wrote
(in article . com):


Here's some news that recently came out:

http://www.newscientist.com/article.ns?id=dn7867

http://abc.net.au/science/news/stories/s1439827.htm

Apparently, soundwaves can help airflow stay near the wing and increase
lift. This can help smaller aircraft to avoid stalling at lower
airspeeds. Is this a technology that could be usefully applied to
existing small aircraft? Or would it require some totally new design
thinking?



I have some of the piezo polymer film they were probably using (from SONAR
experiments, and a steel plate target that tells you where the bullet hit).
The amplitudes would be very small, but covering a wing on an RV or Bonanza
would be less than five pounds in weight, including the high voltage
electrics needed for the piezoelectric material.

But New Scientist is not the most reputable source (called New Age Scientist
by some, ignored by the rest) and I would have to see this confirmed by
another lab. It smells a lot like the kind of signal that screws up your
instrumentation. The drive for the film is likely 800 to 1,200 volts and at
400 Hz running on a little model in a wind tunnel with sensitive detectors of
various sorts. I'll just say I'm skeptical.

-- Charlie Springer


No need to be skeptical on this on Charlie. The technique will work.
Unfortunately, the five pounds of high-maintainence, active equipment
can be replaced with a few ounzes of turbulator strips.

I read one of the NASA reports, done YEARS ago, on the Larc website.
They used the same techique, using sound waves to re-energize the
boundary layer. Pointless was their conclusion if I remember correctly.


--
This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."

In article ,
Ernest Christley wrote:

Charlie Springer wrote:
On Sat, 20 Aug 2005 16:31:43 -0700, wrote
(in article . com):


Here's some news that recently came out:

http://www.newscientist.com/article.ns?id=dn7867

http://abc.net.au/science/news/stories/s1439827.htm

Apparently, soundwaves can help airflow stay near the wing and increase
lift. This can help smaller aircraft to avoid stalling at lower
airspeeds. Is this a technology that could be usefully applied to
existing small aircraft? Or would it require some totally new design
thinking?

I'll just say I'm skeptical.

No need to be skeptical on this on Charlie. The technique will work.
Unfortunately, the five pounds of high-maintainence, active equipment
can be replaced with a few ounzes of turbulator strips.

I read one of the NASA reports, done YEARS ago, on the Larc website.
They used the same techique, using sound waves to re-energize the
boundary layer. Pointless was their conclusion if I remember correctly.

Kinda makes you wonder if they used a particular kind of "noisy" sound
wave, or simple shapes like sine waves.

It'd be really funny if it turned out to work with random or
less-patterned noise, and they missed it because they were too
organized...

--
I don't have a lifestyle.
I have a lifeCSS.

On Sun, 21 Aug 2005 19:22:47 -0700, Chad Irby wrote
(in article ):

Kinda makes you wonder if they used a particular kind of "noisy" sound
wave, or simple shapes like sine waves.

It'd be really funny if it turned out to work with random or
less-patterned noise, and they missed it because they were too
organized...

One would be tempted to think this, but all noise (including triangle and
square waves) can be constructed from a sum of sines and cosines. It is
called Fourier's Theorem, and it works so well nearly all digital signal
processing is based on it to some extent. Note that the researcher's 400 Hz
signal (close to the A flat above middle C) could form some pretty irritating
beats with the engine/propeller. Concert A is 440 and I suspect anybody who
has worked with military aviation is familiar with the sound of the 400 Hz
power systems.

-- Charlie Springer

In article l.net,
Charlie Springer wrote:

On Sun, 21 Aug 2005 19:22:47 -0700, Chad Irby wrote
(in article ):

Kinda makes you wonder if they used a particular kind of "noisy" sound
wave, or simple shapes like sine waves.

It'd be really funny if it turned out to work with random or
less-patterned noise, and they missed it because they were too
organized...

One would be tempted to think this, but all noise (including triangle and
square waves) can be constructed from a sum of sines and cosines.

Technically, yes, but there could be too many situations where "simple"
noise has nothing like the same effect "complex" noise does.

Considering that the airflow across the wings of small aircraft is
generally subsonic, simple versus complex waveforms could make a real
difference (for the generation or prevention of standing waves?).

--
I don't have a lifestyle.
I have a lifeCSS.

On Sun, 21 Aug 2005 22:55:17 -0700, Chad Irby wrote
(in article ):

One would be tempted to think this, but all noise (including triangle and
square waves) can be constructed from a sum of sines and cosines.

Technically, yes, but there could be too many situations where "simple"
noise has nothing like the same effect "complex" noise does.

Considering that the airflow across the wings of small aircraft is
generally subsonic, simple versus complex waveforms could make a real
difference (for the generation or prevention of standing waves?).


Yet the researchers say they used 400 Hz sinusoidal signals and make no
mention of phase adjustments or feedback compensation to null out situations
that would cause detachment.

As for "technically, yes" I would say "and physically". Water waves are a
good example. The bow or stern wave from a boat is not a sinusoid. But there
is dispersion in water surface waves based on wavelength, so sinusoidal
components that can be added together to get the original shape, separate
over time till you see the longest waves leading and the shortest bringing up
the rear. You get a chance to see the "Fourier components" that make up the
original wave, and with no special equipment.

-- Charlie Springer