Abstract:
A direct numerical simulation of advection-diffusion in a sinusoidal tube was
carried out using the commercial finite-volume code STAR-CD. The Reynolds
numbers varied from Re = 0.1 to Re = 14.5. At the larger Reynolds numbers,
steady-state eddies formed in the diverging sections and significantly influenced
the macroscale dispersion. Long tailing was observed in the breakthrough curves.
The results were compared to a 1-dimensional source-sink model using the
semi-analytical solute transport code STAMMT-L. It was found that the results
were generally described by both a single-rate model and a lognormal multi-rate
model. It was observed that the velocity distribution within the inertial regime
had significant influence on dispersion, even at weak inertial flowrates which did
not experience flow separation.
