On the dispersion of a solute in pulsating flow through a tube

Abstract

The effective dispersion coefficient of a solute in pulsating flow through a circular tube is here found. The case of a viscous flow under a pulsating pressure gradient is treated in detail and it is found that the Taylor diffusion coefficient contains terms proportional to the square of the amplitude of the pressure pulsations. However, the coefficients of these terms tend rapidly to zero, and the effect of pulsation will rarely contribute a fraction of more than 1/128 (the ratio of the amplitude of pressure gradient pulsation to mean pressure gradient) 2 to the total dispersion coefficient. The methods may be applied to diffusion in any periodic flow.