Item 1085
DESIGN: UniCopter ~ Vibration -
Rotor Induced - Control - Boundary-Layer (BLC)
The following conjures up the idea of using electricity to modify the aerodynamic profile of the blade, without changing it's physically profile. This may allow rapid changes in its lift, many times in a single revolution.
~ OR ~ It may increase the maximum coefficient of lift but do NOTHING to improve the actual thrust (angle of attack). It is this temporary increase in the actual thrust that is required.It seems that the idea might have merit for reducing the rotor to rotor vibration experienced by an intermeshing configuration. A high voltage intermittent discharge, similar to a car's ignition system, might provide a short duration pitch increase in the middle third of the lower blade, as it passes through the downwash of the upper blade's outer portion.
A thought: Boundary-Layer Control may not overcome the rotor to rotor induced vibration. This is because the blades will normally be operating at a low angle of attack and when they experience the downwash/downdraft from the other rotors blade the angle of attack will be even less. The separation point on the upper blade may already be so far aft that BLC will offer nothing.
If this was done at the root end and there was a good amount of twist, then it might be more effective.
Would a pulsed Coanda effect provide any possibility of short duration changes in the angle of attack?
Ions:
http://www-spof.gsfc.nasa.gov/Education/wposion.html
Can the air be ionized in front of the magnets?
Post question to NG
Polutants in air might increase ion count but this is no problem since the CPU will adjust for it.
Boundary-Layer Control:
http://www.fz-rossendorf.de/FWS/FWSH/EBLC/eblc.html
http://www.fz-rossendorf.de/FWS/FWSH/EBLC/separation-control/separation-control.html
http://www.chemistry.nmsu.edu/~research/ion_mobility/moreims.html
Lorentz forces ~ ~ Electromagnetic (Lorentz) Forces
Electromagnetic Boundary Layer Control
International Workshop on Electromagnetic Boundary Layer Control
:(EBLC)for Saltwater Flows, Dresden, July 7-8, 1997. Electromagnetic fields located on the surface of some immersed body allow to introduce a Lorentz force distribution in the vicinity of the body surface. It can be adapted to the fluiddynamical needs by suitably varying the magnet and electrode configurations. This idea offers several control possibilities for saltwater flows like:
It is a very recent topic of fluiddynamical activities. A huge field of applications can be expected. Therefore, an international workshop is organized to summarize the state-of-the-art, and to discuss next steps in that field.
Invited lectures will be given by Dan Nosenchuck (Princeton), Jim Meng (Newport), John Kim (Los Angeles), Linda Kral (McDonnell Douglas, St.Louis), Mohamed Gad-el-Hak (Notre Dame), and George Karniadakis (Providence).
Besides presenting recent results strong emphasis will be placed on discussions during the workshop. The workshop will be held in Dresden (Germany). Further information can be obtained from:
Electrical conductivity is a measure of the ionic concentration (anions and cations present) of the sample.
Typical electrical conductivity values of between 50 - 150 represent 'clean waters' i.e. have few contaminants present and offer a low buffering potential.
Electrical conductivity is measured in Ms m-1 (or umhos cm-1) units.
A problem on air 
What is the relationship of the electrical conductivity of air and the altitude of the air? Or put another way is air more conductive at sea level or at 10000 feet above sea level?
Electrical conductivity of air
A charged electroscope will discharge in time, even when it is well isolated; in one way or another the charge leaks into earth's atmosphere. The rate of discharging is a measure for the electrical conductivity of air. Can this electrical conductivity roughly be estimated by measuring the decrease of the pointers' deflection?
Welcome to the sci.physics.plasma newsgroup.
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8. WHAT IS A PLASMA?:
The loosest definition of a plasma is that it is an electrically
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gas are tightly bound inside gas atoms and are not free to move in
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Under certain conditions, however, some or all of the electrons can be
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There are three principal methods for ionizing a gas. The first, called
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Newspaper Article on IONS AND AIR RESISTANCE
by Michael Higgins, National Post, May 18, 2002Students' winning work may make cars, planes faster.
Science fair winner hailed as breakthrough.
Two Grade II students are being credited with a breakthrough in technology that could allow vehicles to travel faster in the future.
Mahvish Jafri and Faizal Ismail, both-l6, yesterday won the top prize at the Canada-Wide Science Fair for an invention that, in tests, reduced drag by 31%.
If the results can be transferred from the laboratory to practical engineering their technique could revolutionize travel.
"To reduce drag by 31% is incredible," said Prof. Marilyn Lightstone of McMaster University. "But the results would have to be vigorously tested."
"Some people spend their whole careers trying to reduce drag," said Prof. Lighstone, of McMaster's department of mechanical engineering.
The two Toronto students took the "Best of Fair" prize in Saskatoon after demonstrating how to limit "boundary layer acceleration" - overcoming some of the slowing effects of air resistance by generating an electrical field.
"If you pass an electrical field over the surface going through the air, it creates ions that lower the air pressure," explained Glen Stone, a spokesman for the Youth Science Foundation. "It has tremendous application."
He said reduced air resistance would enable cars and planes to go faster and would reduce fuel consumption. In wind-tunnel experiments involving various aerofoils, the students' technique reduced drag by 31%. Mr. Ismail said they began looking at a project for Sci-Tech Ontario involving "plasma physics," but then changed to "fluid mechanics." They combined the two to come up with their idea for reducing drag. "We first did a theoretical study," Ms. Jafri said. "We got pretty much what we expected, but then it was very exciting to develop it and prove the theory." She said she believed the idea had not been developed before because no one had thought about combining plasma physics and fluid mechanics.
The students plan to look into the possibility of patenting the idea.
Mr. Stone said the technology still needs to be developed to ensure the power created to reduce the air pressure did not negate the beneficial effects.
Ms. Jafri and Mr. Ismail, from Toronto's Marc Garneau Collegiate, were chosen over nearly 500 other top young scientists from across the country in the competition at the University of Saskatchewan.
The pair also won Best Senior Project as well as a Gold Medal in Engineering Division. They won more than $20,000.00 in prizes.
Replies:
Thanks for the article. Unfortunately, the idea is neither new nor easy or practical to implement. Regardless of the merit of the idea, though, it's always great to see kids excited about these things. They *will* come up with some breakthrough sooner or later. ~ RC
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Tesla was always tinkering along the lines of fluid machines combined with electrical fields, and I think he might have experimented with something like this, perhaps even patenting it. ~ SW
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This is a difficult concept from an engineering perspective.
Plasma physics deals with electrically ionized gases, which can be controlled by either magnetic or electrostatic means. I looked, and there's a huge number of properties associated with plasmas (thus my concern for the engineering difficulties). Some of them include the following, from an online dictionary of plasma physics at the Fusion Energy Educational Website.
I think that in their experiment, the lowered air pressure may have come about due to the electrostatic repulsion of the ionized air molecules. For the air flowing over the wings, a charge generator would need to provide a constant electrical output in order to continually ionize the air passing over the wing. That would just be the beginning of the engineering problems.
I think it would take a great deal of work to both verify their experiment, and to also quantify the exact behavior of ionized air passing over a wing. Just look at the entries in the plamsa dictionary to get an idea of just how many physical properties plasmas have. ~ Flight Safety
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What happens when it rains? ~ 400 Hertz
WHAT IS A PLASMA?:
Related Patents:
6,109,566 ~ Vibration-driven acoustic jet controlling boundary layer seperation
5,320,309 ~ Electromagnetic device and method for boundary layer control
5,964,433 ~ Staggered actuation of electromagnetic tiles for boundary layer control
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