Hemodynamics
of
Large Arteries
123
towards the vessel wall, such that at the arterial wall, the velocity is the
lowest (Fig. 4.5.1).
In the arterial system, the velocity profile is
relatively flat or blunt at the entrance, or at the ascending aorta and
becomes progressively parabolic when approaching smaller arteries.
5t
velocity
pmfik
Fig.
4.5.1
:
Different velocity profiles.
A
blunt
or
flat velocity profile (bottom tracing) is
when the blood velocity across the vessel is uniform, mostly find in large vessels, such as
the proximal aorta.
A
parabolic velocity profile
(top
tracing)
is
when the centerline
velocity is the highest with decreasing velocity towards the arterial wall, occurring
largely
in
arteries, such as the femoral.
A
skewed velocity profile is when the blood
velocity
is
high towards one wall than the opposite side.
Lamb
(1
898)
later assumed an inviscid fluid contained within a thin-
walled tube (h<<r) subject to small strains and arrived at equations
of
motion for the wall:
1
(
+-L
at
1-0~
dz2
r
az
E
d2u,
o
du
~-
d2U,
-
PW-j-
-
(4.5.12)
(4.5.13)
