Children playing in the sea never tire of trying to catch the little fish that swim close to shore with their bare hands. The fish sense the danger and can escape by reaching accelerations of up to ten times the gravity acceleration within a fraction of a second. This unimaginable acceleration explains why it is virtually impossible to catch a fish with our bare hands, although they seem to be near and within our grasp. Millions of years of evolution have allowed the larval fish to develop an efficient escape mechanism: they bend their bodies into a ‘C’ shape before they flee away from their predators. Observations and experiments have speculated that this so-called C-start is an optimal design developed over millions of years of evolution.

C-start hypothesis tested using a supercomputer

Petros Koumoutsakos, a professor at the Computational Science & Engineering Laboratory at ETH Zurich, and two of his doctoral students, Mattia Gazzola and Wim Van Rees, have now provided the quantitative confirmation regarding the optimality this C-start hypothesis, which had been missing to date. They have also made further discoveries regarding the hydrodynamics involved in the process.