Class: BE310
Group: M2
Members: Ronit Morris, Devjani Saha, Toby Tisserand
Date:May, 2002
Abstract:
Dye streamlines through two symmetric aneurysm models with different
radii were visualized in order to determine the critical Reynolds number
corresponding to the onset of turbulent flow. The critical flow rate for
which the onset of turbulence occurred at the center of the model was determined
by timed collection of fluid. This flow rate, along with the aneurysm radius
and dynamic viscosity of the fluid was used in the calculation of the critical
Reynolds number. The experiments were conducted using sucrose solutions
of varying viscosities in order to verify that the critical Reynolds number
at the onset of turbulence was independent of fluid viscosity, within one
model of a specific geometry. The average critical Reynolds numbers were
10310 +/- 305 and 10620 +/- 104 in the large model and small model, respectively.
The onset of turbulence was determined to be a function of NREcrit and
[a/b]n where a/b equals the radius of inlet tube/radius of aneurysm and
n is a constant. The value of n was determined to be 0.05 +/- 0.017. These
data were compared and the critical Reynolds number was found to be statistically
the same for both models, indicating that the value of n might actually
be closer to zero. Therefore, the onset of turbulent flow has a small dependence
on the geometry of the model, namely a/b, and a large dependence on the
critical Reynolds number .