Numerical and experimental results on the dispersion of a solute in a fluid in lamin/ar flow through a tube

The longitudinal dispersion of a solute is studied for the process in which pure solvent slowly displaces solution in a circular tube. Good agreement is obtained between a numerical solution of the partial differential equation describing the process and experimental results for water displacing a dilute solution of potassium permanganate. The range of applicability of Sir Geoffrey Taylor’s approximate solution is discussed. An improved approximate solution is presented with a much wider range of validity. This improved approximation is based on the numerical solution of the equation describing the process.