Advanced Topics and Future Trends - Computational Hemodynamics: Theory, Modelling and Applications - page 306

Chapter 9
Advanced Topics and Future Trends

9.1 Introduction

This chapter considers the latest research capabilities in haemodynamics. Signifi-
cant progress in computational modelling has been made in the last few decades.
These advances along with increased computational power will further enable mod-
elling realistic physiological scenarios of haemodynamic flows. The material pre-
sented in this topic thus far serves as an introduction to some of the current trends
and modeling capabilities. In this chapter the latest developments of some research
fields of haemodynamics including microflow analysis of blood, medical maging
for flow analysis, advanced medical devices, and heart valves are explored.

9.2 Blood Rheology

9.2.1 Multiphase Flow

Single phase flow refers to a one phase flow where the fluid does not change state
during temperature changes whereas a multiphase flow displays a variety of pattern
behaviours such as droplets, bubbles, slugs as well as films. Single-phase modelling
may be applicable in large arteries such as aorta and some larger coronary arteries in
the heart. However it is not appropriate for explaining blood flow behaviour when
blood vessel diameters are small and within the same order as the red blood cells
( d ~ 10 µm).
Blood at physiologic conditions is a dense suspension of cells and platelets dom-
inated by red blood cells. In most cases, they are the blood component principally
responsible for its rheology.
The flow regime is termed sub-Stokesian (Re ~ 0.01) where the local environ-
ment remains predominately viscous. However at these flows, the red blood cells
are significantly distorted due to their flexibility leading to a change in its effective
viscosity and frictional resistance.