Document Type




Embargo Period



spheres, sedimentation, sediments, equations of motion, stokes law, symmetry, particle size, numerical solution, multipoles, series expansion, viscosity, fluids


Chemical Engineering


Exact periodic solutions are found for the relative motion of three spheres sedimenting in a Stokes fluid. Nearby solutions are found to be nearly periodic for a long time. Existence of the exact periodic solutions is proved using the point-particle approximation and symmetry properties of Stokes equations. Numerical simulations for finitie-sized particles are performed using a method of multipole expansions.

Additional Information

Copyright 1988 Physics of Fluids. This article may be downloaded for personal use only. Any other use requires prior permission of the author and Physics of Fluids. The article may be found at



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.