arXiv subjects

Tirion G. Roberts

Publications and source records attributed to Tirion G. Roberts.

3 recordsLinked to original sources

arXiv2020

Characterisation and optimisation of foams for varicose vein sclerotherapy

In this study we characterise the properties of foams used for varicose vein sclerotherapy. Their effectiveness is evaluated by predicting their yield stress and their flow profiles within a model of a vein. This information is represented using a Bingham number, which also takes into account the foam liquid fraction and the Sauter mean of the bubble size distribution. Based on this modelling, the most effective foams have a Bingham number B = 600 for a vein of diameter 2mm, in addition to a narrow bubble size distribution.

cond-mat.soft↗

arXiv2020

An analytic velocity profile for pressure-driven flow of a Bingham fluid in a curved channel

We derive an expression for the velocity profile of a pressure-driven yield-stress fluid flow-ing around a two-dimensional concentric annulus. This result allows the prediction of the effects of channel curvature on the pressure gradient required to initiate flow for given yield stress, and for the width of the plug region and the flux through the channel at different curvatures. We use it to validate numerical simulations of the flow from a straight channel into a curved channel which show how the fluid first yields everywhere before reaching the predicted velocity profile.

physics.flu-dyn↗

arXiv2019

Semi-analytic velocity profile for a Bingham fluid in a curved channel

We derive an expression for the velocity profile of a pressure-driven yield-stress Bingham fluid flowing around a 2D concentric annulus. The formula requires the numerical solution of a nonlinear equation for the positions of the yield surfaces. The results allow the prediction of the effects of channel curvature on the pressure gradient required to initiate flow for given yield stress, and for the width of the plug region and the flux through the channel at different curvatures.

physics.flu-dyn↗