PubMed Health⌕ Search

Biomedical subjects

P Poesio

Publications and source records attributed to P Poesio.

2 recordsLinked to original sources

Effects of quenching rate and viscosity on spinodal decomposition.

Spinodal decomposition of deeply quenched mixtures is studied experimentally, with particular emphasis on the domain growth rate during the late stage of coarsening. We provide some experimental evidence that at high Péclet number, the process is isotropic and the domain growth is linear in time, even at finite quenching rates. In fact, the quenching rate appears to influence the magnitude of the growth rate, but not its scaling law. In the second part of the work we analyze the effect of viscosity on the growth rate. As predicted by the diffuse interface model, we do not find any effect of viscosity on the growth rate of the nucleating drops, although, as expected, the viscosity of the continuous phase does influence the settling speed and thus the total separation time.

Journal Article↗

Stationary core-annular flow through a horizontal pipe.

A theoretical investigation has been made of core-annular flow: the flow of a high-viscosity liquid core surrounded by a low-viscosity annular liquid layer through a horizontal pipe. Special attention is paid to the question how the buoyancy force on the core, caused by a possible density difference between the core and the annular layer, is counterbalanced. From earlier studies it is known that at the core surface ripples are present that have the shape of "bamboo" waves or "snake" waves. They generate pressure variations and secondary flows in the annular layer that can cause a net hydrodynamic force on the core. Using hydrodynamic-lubrication theory (assuming the core to be rigid) it has been shown that for snake waves the lubrication force can counterbalance the buoyancy force. For bamboo waves that is not the case.

Journal Article↗