> > On Tue, 12 Jun 2007 10:36:57 +0200, "Michel Jullian" <[EMAIL PROTECTED]> > wrote: > >Applications of EHD to aircraft aerodynamics has been a subject of > >intense research recently, lookup e.g. OAUGDP. > > > >Why _piezo_ ceramic tiles BTW?
Suppose that polyethelene-covered conductors at AC high frequency can produce plasma layers. If instead we use high-K dielectric like barium titanate or PZT, then the same plasma effects will also occur at lower AC frequency (perhaps several thousand times lower freq than with PE plastic.) Also, a ceramic insulator would better survive damage from corona effects. And, if the ceramic contains no carbon, then an arc-through would self heal after the melted material cooled down. If military aircraft are seen to be covered with barium titanate, well, perhaps it's an antireflector coating for radar. Or perhaps it's there for creating a plasma layer whenever the aircraft is electrically driven with a huge voltage. Where AC is concerned, dielectric materials resemble conductors. For example, place some dielectric pucks upon a metal electrode, then drive that electrode with HV at high frequency. If any plasma streamers were to appear, they would leap from the tops of the dielectric pucks, and not from the metal surface. (((((((((((((((((( ( ( ( ( (O) ) ) ) ) ))))))))))))))))))) William J. Beaty SCIENCE HOBBYIST website billb at amasci com http://amasci.com EE/programmer/sci-exhibits amateur science, hobby projects, sci fair Seattle, WA 425-222-5066 unusual phenomena, tesla coils, weird sci
