For the Fall iteration of MCEN 5151 at CU Boulder (aka FlowVis), I wanted to capture the fluid flow around a swimmer. We can visualize the flow around a swimmer during a butterfly or “dolphin” kick performed sideways in a body of water (in this case a flume) by backlighting the flow with a light on the ceiling. The light catches the bubbles created when the upper legs drags along the surface of the pool. These bubbles act as “particles” that mark the boundary of vortices and turbulence from the kicking-induced flow.

Shot on a GoPro 11 Black at 4k and 120 fps using the wide angle lens. The camera was placed at the bottom of a Swim Spa or “swimming flume” (the flume was not running during this video). An overhead LED light illuminated the flow while the swimmer (me) kicked dolphin kicks on her left and right sides.