Quote:
Originally Posted by freebeard
That's helpful. Link?
Is it like the anti-gravity stuff on the B-2 bomber?
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I've read through so many of them, I'm unsure if this is the exact one I referenced, but it's pretty easy to Google for any number of studies, just search for "aerodynamic drag reduction by energy deposition", "subsonic aerodynamic drag reduction by energy deposition" and similar variations:
Brown.edu Research Projects (PDF)
"The energy was deposited instantaneously along a finite length of the cone axis, ahead of the cone's bow shock, causing a cylindrical shockwave to push air outward from the line of deposition. The shockwave would sweep the air out from in front of the cone, leaving behind a low-density column/tube of air, through which the cone (vehicle) propagated with significantly reduced drag. The greatest drag reduction observed was 96% (100% drag reduction would result in the complete elimination of drag forces on the cone). The propulsive gain was consistently positive, meaning that the energy saved due to drag reduction was consistently greater than the amount of energy "invested" (i.e. deposited ahead of the vehicle). The highest ratio of energy-saved/energy-invested was approximately 6500% (a 65-fold "return" on the invested energy)."
Here's another good one:
Nonequilibrium Plasma Aerodynamics (PDF)
"Promising applications of plasma systems to control flow involve management of laminar-to-turbulent transition in the boundary layer, the management of flow detachment or attachment to the surface, and the resultant management of lift and drag force of an airfoil.
The authors [Mhitaryan et al, 1961, 1964] demonstrated up to 30% drag force decrease and 40% lift force increase for airfoil with 460 mm chord length (AoA = 8 degrees), thickness of 13% and flap length 30% (AoA = 43 degrees) of the chord in velocity range from 8.75 to 20.4 m/s."