LOL wait until the boys around here get ahold of that one-- “Oh sniff well that’s just wrong–surfboard fins are nothing like airfoils–why, for that matter, air is nothing like water, and this lift you speak of has nothing to do with drive, man.”
; )
On a serious note, I was checking out a book on dynamic swimming, and note that the rotation about the axis the paper talks about is usable and visible with surfboard fins, swimmers’ hands, dolphins’ and sharks’ dorsal fins, and birds’ flapping wings. I love this stuff
They say that some dolphins’ fins generate lift in the same way as delta wing aircraft. Using Computer tomography scanning of the fins of seven different
species ranging from the slow swimming Amazon River dolphin and pygmy
sperm whale to the super-fast striped dolphin, the team made scaled
models of the flippers of each species. Then they measured the lift and
drag experienced by the flipper at inclinations ranging from -45deg. to
+45deg. in a flow tunnel running at a speed that would have been the
equivalent of 2m/s for the full scale fin. Commenting that environmental and performance factors probably play a
significant role in the evolution of dolphin and whale flipper shapes
and their hydrodynamics, Howle and his colleagues are keen to find out
more about the link between the flippers’ performances and the
environment that whales and dolphins negotiate on a daily basis.