John Tsamopoulos

TL;DR: In this article, a finite element/Newton method is presented for solving the free-boundary problem composed of the velocity and pressure fields and the yield surfaces for creeping flow, and the accuracy of solutions is ascertained by mesh refinement and by calculation of the integrals corresponding to the maximum and minimum variational principles for the problem.

TL;DR: The dynamic response of an initially spherical capsule subject to different externally imposed flows is examined in this article, where two constitutive laws are used for the description of the membrane mechanics, assuming negligible bending resistance.

TL;DR: In this article, moderate-amplitude axisymmetric oscillations of incompressible inviscid drops and bubbles are studied using a Poincare-Lindstedt expansion technique, and corrections to the drop shape and velocity potential caused by mode coupling at second order in amplitude are predicted for two-, three-and four-lobed motions.

TL;DR: In this article, the authors examined the buoyancy-driven rise of a bubble in a Newtonian or a viscoplastic fluid assuming axial symmetry and steady flow, and determined the nodal points of the computational mesh by solving a set of elliptic differential equations to follow the often large deformations of the bubble surface.

TL;DR: In this article, the axisymmetric squeeze flow of a viscoplastic material is examined and the deformation and flow of such materials are important, since many multicomponent fluids encountered in industrial processes, are viscplastic.