Case Studies of the Human Cardiovascular System - Computational Hemodynamics: Theory, Modelling and Applications - page 186

Fig. 7.5 Procedural flow
chart for experimental and
numerical studies. The
presentation of a system-
atic approach to perform
experimental and numeri-
cal data acquisition and
comparison can allow us to
compare the predicted and
experimentally derived flow.
Data retrieval and anatomi-
cal reconstruction based on
MRI generates a geometri-
cal model. Then, the rapid
prototyping of the model that
is followed by PIV measure-
ment of flow within it, and
numerical simulation using
the same anatomical model
are performed. The predicted
data from simulation and the
experimentally measured
flows are examined in the
final stage

conditions when setting the numerical framework. In the case of cardiovascular
anatomies, velocity-encoded phase contrast MRI or ultrasound, are typically used
to extract the flow values at the inlets and outlets of the anatomical structures to be
used as boundary conditions for the computer models.
Figure 7.6 shows a schematic diagram of an experiment setup for PIV
measurement. The experimental flow loop comprises of a silicone phantom, an
elevated fluid tank, a flow meter and a suction pump. To eliminate refraction of
the laser sheet, the index of refraction of working fluid was specifically chosen to
match the refraction index of the phantom wall. The working fluid was a mixture of
glycerol (55 % by mass) and distilled water (45 % by mass), which has a refraction
index of 1.42 and kinematic viscosity of ν = 6.2×10 −6 m 2 /s at constant tempera-
ture of 25 °C. In this case study the kinematic viscosity of human blood is taken
as 3.4 × 10 −6 m 2 /s. Considering that the kinematic viscosity of the mixture and the
phantom are scaled-up by 10 times, the flow rate of the working fluid can be es-
tablished based on dynamic similarity. A flow Reynolds number (Re) of 485 was
determined at the flow phantom inlet boundary, corresponding to a typical flow rate
at the common carotid artery (CCA) (i.e. 12.17 ml/s) of a healthy adult at the peak
of cardiac cycle (Tada and Tarbell 2005). The flow rate of the working fluid can be
determined by

ν
ν

m

Q = 10 Q , (7.3)

m b

b