Meeting Abstract
In biomechanics classes, many of us have been shown the classic figure of pressure along a fish’s body during swimming: high pressure on the head, negative pressure along much of the body, and positive pressure on the caudal fin. This figure was the result of a series of seminal works by Dubois and colleagues, who implanted pressure sensors into the skin of fish to measure the pressure gradients generated by their carangiform swimming movements. Using our new techniques for quantifying pressure and force distributions at high temporal and spatial resolutions, we revisit these findings. On average, the profile matches the classic figure. But instantaneously, the pressure gradients oscillate substantially around this average. Negative pressure contributes on average 42% of total thrust, and the anterior body produces 36% of total thrust. Further, temporal patterns of positive and negative pressure around the caudal fin suggest that negative pressure may play a key role in the timing of thrust delivery. These relatively subtle shifts can substantially change thrust production during swimming, and since swimming is an essential component of many fish behaviors, it is tied to the evolution of fish body forms and ecological roles. By leveraging these new methods to understand force production mechanisms, future work will reveal evolutionary pressures leading to the diversity of body forms we see in fishes today and inspire designs for fast, efficient underwater vehicles.
