You have to wonder if the NA wasn't inspired by the ventral pleats of the Blue Whale. Supposedly, when excited, they can attain 20 mph submerged. I wonder if that is 'because of' or 'in spite of' the pleats. I'll bet the folks at the Naval Submarine Base New London in Groton, CT. might know a thing or two about that.
"For about 20 years it has been known that special microstructures (“riblets”) can lower drag by up to 10%. A new process for the production of such microstructured coatings on large surfaces is presented in this article. This process allows coating application, embossing, and partial curing in a single step. The coating material consists of VOC-free nanocomposites that give the coating the necessary abrasion resistance and weathering stability.
Drag measurements have been carried out in a ship model basin and in a wind-tunnel respectively. In these experiments, smooth coatings were compared to riblet-structured coatings. These structures were adapted to the flow-parameters of the fluid. A surface-drag reduction of 5.2% for a torpedo-shaped specimen was measured in a large hydrodynamic and cavitation tunnel. In a wind-tunnel experiment a reduction of the total drag of a wing-profile by 6.2% was measured.
Both experiments indicate the high potential for fuel savings in the transportation sector."
http://www.sciencedirect.com/science/ar ... 4010003206
Or the latest in performance swimmer's gear . . . . "Secondary function being whale's skin has parallel lines which help eliminate turbulence and allow it to swim faster and more efficiently. Laminar flow occurs when fluid flows in parallel layers, eliminating disruption in the flow, also known as called turbulence. The Finishline’s parallel ribbed chest, back, and legs significantly reduce flow turbulence while increasing speed and efficiency, improving hydrodynamics and speeding your passage through the water, with less fatigue."
Just some food for thought