The Reynolds number is given by
Re = ρVL/μ
where L is the characteristic length.
It is assumed that the blood vessel is not collapsible, which means
the vessel wall is not deformable, and the stenosis scenario (i.e., constriction
or narrowing of coronary vessels due to the buildup of fat and cholesterol)
is not considered. Since the blood vessel maintains the circular cross
section, the diameter (D) is chosen as the characteristic
length, which is 10-5 m.
At body temperature, the density (ρ) and viscosity (μ) of the plasma is given as 980 kg/m3 and
0.0014 N-s/m2, respectively. Since the plasma consists 90% of water, the density and viscosity of plasma are close to thase
of water (ρ = 999 kg/m3 and μ = 0.0011 N-s/m2).
The Reynolds number is calculated to be
Re = (980)(2.25)(10-3)(10-5)/(0.0014)
Based on the pipe flow model, the calculated Reynolds number is less
than 2,100, hence the flow is laminar.