Authors Dimakopoulos Y., Pavlidis M., Tsamopoulos J. Abstract The steady, buoyancy-driven rise of a bubble in a Herschel-Bulkley fluid is examined assuming axial symmetry. The variation of the rate-of-strain tensor around a rising bubble necessitates the coexistence of fluid and solid regions in this fluid. In general, a viscoplastic fluid […]
Free surface flow
9 posts
Authors Papaioannou J.G., Dimakopoulos Y., Tsamopoulos J.A. Abstract Because of the three dimensional nature of many physical problems encountered in industrial processes and applications, we develop a novel 3D elliptic grid generator for the construction and the deformation of structured grids. The specific application we consider is related to the […]
Authors Housiadas K., Tsamopoulos J. Abstract The effect of the air jet, which is used to increase the process stability and cool the polymeric film which is produced by the widely-used Film Blowing Process (FBP) is presented. The air jet is supplied circumferentially and tangentially on the outside surface of […]
Authors Dimakopoulos Y., Pavlidis M., Tsamopoulos J. Abstract We examine the pressure-driven coating of a straight tube with a viscoelastic liquid using an advanced and stable finite element algorithm, which is based on an elliptic grid generator along with local refinement and reconstruction of the mesh wherever this is needed. […]
Authors Karapetsas G., Tsamopoulos J. Abstract The steady extrusion of viscoelastic materials from a straight, annular die is studied theoretically. The viscoelastic behavior is modelled using the affine Phan-Thien and Tanner (PTT) constitutive equation of the exponential form. For the numerical solution of the governing equations the mixed finite element […]
Authors Karapetsas G., Tsamopoulos J. Abstract The transient, axisymmetric squeezing of viscoplastic materials under creeping flow conditions is examined. The flow of the material even outside the disks is followed. Both cases of the disks moving with constant velocity or under constant force are studied. This time-dependent simulation of squeeze […]
Authors Dimakopoulos Y., Tsamopoulos J. Abstract We examine the transient displacement of a viscoplastic material from straight or suddenly constricted cylindrical tubes of finite length. Our general goal is to develop accurate and efficient numerical methods for the fundamental study of processes in which a gas is displacing a liquid […]
Authors Tsamopoulos J.A., Chen M.F., Borkar A.V. Abstract The spin coating of a viscoplastic material is studied using a continuous viscosity function. Thus, the transient model requires the calculation of only velocity, pressure and the moving-free surface of the liquid film, but not the calculation of the yield surface within […]
Authors Pelekasis N.A., Tsamopoulos J.A. Abstract A numerical study on the dynamic behaviour of a charged and conducting drop, with net electrical charge Q, is presented here, that is valid for arbitrary initial disturbances. It employs the integral form of Laplace’s equation for the calculation of the velocity and electrostatic […]