Ar. Galper et T. Miloh, MOTION STABILITY OF A DEFORMABLE BODY IN AN IDEAL FLUID WITH APPLICATIONS TO THE N SPHERES PROBLEM, Physics of fluids, 10(1), 1998, pp. 119-130
The Liapunov stability problem of the translation or spiraling motion
of an arbitrary deformable body (the deformation of which is governed
by the corresponding Hamiltonian) is treated here using the modified E
nergy-Casimir approach. The appropriate stability criteria are derived
. It is shown that some unstable translational motions can be stabiliz
ed by a deformational or rotational motion. This formalism is further
applied to the stability problem related to the motion of N (generally
unequal) rigid spheres embedded in a potential flow field. The assemb
ly of N-spheres is treated as an entire N-connected single deformable
body. The Liapunov stability of the motion of two spheres in the direc
tion orthogonal to their Lines of centers and that of three spheres in
the direction orthogonal to their plane of centers, is demonstrated a
nd proven as a special case. Some existing conditions of clustering fo
r a bubble cloud are also rederived and extended. (C) 1998 American In
stitute of Physics.