A mechanical model of swimming using two-link extremities

The motion of a multilink mechanical system in a liquid, which models the swimming of some animals (the frog) using a pair of extremities, is investigated. It is assumed that the liquid acts on the moving bodies through forces that are proportional to the squares of their velocities. Periodic motions of the system are constructed. The mean velocity of motion of the system is estimated and its dependence on parameters of the motion is shown.