The physics of swimming fish

23 junio 2015

Fish may seem to glide effortlessly through the water, but the tiny ripples they leave behind are evidence of a constant give-and-take of energy between the swimmer and its aqueous environment — a momentum exchange that propels the fish forward but is devilishly tricky to quantify. Now, new research shows that a fish’s propulsion can be understood by studying vortices in the surrounding water as individual units instead of examining the flow as a whole.