A Boundary Element Model Of Vascular Gas
Bubble Sticking And Sliding
Author(s)
B. Eshpuniyani & J. L. Bull
Abstract
A two dimensional channel flow in which a bubble adheres to one of the walls
is studied computationally. The flow regime of interest here corresponds to very
low Reynolds numbers. This allows us to model the flow using Stokes equations.
The numerical method used is the boundary element method (BEM). A Tanner
law is used to model the moving contact line dynamics. Both hydrophilic and
hydrophobic channel walls are considered. The evolution of the bubble interface,
pressure and velocity fields, and wall normal and shear stresses are studied for
different values of inlet to outlet pressure ratios. The wall normal and shear stresses
peak at the contact lines. It is shown that the horizontal force acting on the bubble
approaches a constant value as the simulation progresses in time.
1 Introduction
A two dimensional channel flow in which a bubble adheres to one of the walls
is studied computationally. This study is a part of an investigation into using a
gas embolotherapy based technique for cancer treatment. This potential treatment
modality uses gas bubbles to occlude blood flow to a tumor, thereby inducing
tumor necrosis. The bubbles originate as perfluorocarbon droplets that are small
enough to pass through capillaries. Low intensity ultrasound is used to track their
motion.At the desired location the bubbles are vaporized using high intensity ultrasound
to produce gas bubbles which are several times larger than the initial droplet
size ([1, 2, 3, 4, 5, 6, 7]). These bubbles then stick in the vasculature, occluding the
flow. The bubble sticking process likely involves the bubble contacting the vessel
wall and then either sticking immediately or sliding some distance before becoming
stuck or detaching from the wall. The effectiveness of the technique depends
on where the bubbles stick and how much of the flow they occlude. In addition to
Keywords
Related Book
Other papers in this volume
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