'Blood flow' is the flow of
blood in the
cardiovascular system. The discovery that blood flows is attributed to
William Harvey.
Mathematically, blood flow is described by
Darcy's law (which can be viewed as the fluid equivalent of
Ohm's law) and ''approximately'' by Hagen-
Poiseuille's law (as it is accurate only for
Newtonian fluids, while blood flow is not Newtonian and its flow can be described as
laminar only in smaller vessels, elsewhere it is
turbulent). The first equation below is Darcy's law, the second is the Hagen-Poiseuille law:
:
:
where:
| :F = blood flow:P = pressure:R = resistance:ν = fluid viscosity | :L = length of tube:r = radius of tube |
In the last equation it is important to note that resistance to flow changes dramatically with respect to the radius of the tube. This is important in
angioplasty, as it enables the increase of blood flow with
balloon catheter to the deprived organ significantly with only a small increase in radius of a vessel.
See also
★
Heart rate