Meeting Abstract

S11.6  Wednesday, Jan. 6  From optimized swimming performance to optimal body shapes TOKIć, Grgur*; YUE, Dick K.P.; Massachusetts Institute of Technology; Massachusetts Institute of Technology yue@mit.edu

We address the question of whether the body geometry and motion characteristic of fish can be deduced directly from mechanical and hydrodynamical considerations. The mechanics and fluid mechanics of fish swimming has been widely studied in recent years, from experimental as well as from the computational standpoint. Hydrodynamical studies have generally focused on the analysis of flow structures around the fish body and the implications those might have on swimming performance. Other studies have as their objective modeling of the fish body and motion from structural/mechanical aspects. Dynamical studies have also been made to model the motion of the fish for given neural activations of the muscles. In these studies, however, the body shape and/or the motion are generally always prescribed. Our interest is in the inverse problem, namely whether the consideration of some notion of optimality in terms of the hydrodynamics, structural mechanics and muscular behavior may lead to specific “optimal” body shapes and swimming characteristics. Of significant obvious interest, of course, is whether such mechanically deduced shapes and characteristics are indeed observable in nature; and in some sense, therefore, not to answer how fish swim, but to possibly answer why they look and swim the way they do. To answer this question, we build an integrated model for fish swimming and combine the model with select performance objectives to find optimal “designs” in terms of morphological parameters relevant for locomotion. Our results show that the body shapes and motions obtained, as a consequence of optimization based on the swimming performance, in many cases offer strong resemblance to those of undulatory swimming organisms observed in nature.