ON THE MOTION OF A NONRIGID SPHERE IN A PERFECT FLUID

We consider in the paper the problem of the motion of a slightly defor mable sphere embedded in a non-uniform potential flow-field. It is dem onstrated that up to the first-order in the surface-deformation amplit ude, the equations for the linear and angular velocities are uncoupled . After deriving the dynamic equations by accounting for the small sur face deformations, we treat the phenomenon of the body's self-propulsi on and point out to a qualitative difference between the self-propulsi on of a deformable sphere in a quiescent or uniform surrounding and, t hat in a non-uniform ambient flow-field. The effect is more significan t (by an order of magnitude) in the latter case. Also discussed is the corresponding parametric resonant interaction as a possible mechanism for self-propulsion.