Taylor dispersion is an effect in fluid mechanics in which a shear flow can increase the effective diffusivity of a species. Essentially, the shear acts to smear out the concentration distribution in the direction of the flow, enhancing the rate at which it spreads in that direction. The effect is named after the British fluid dynamicist G. I. Taylor. Taylor dispersion is an effect in fluid mechanics in which a shear flow can increase the effective diffusivity of a species. Essentially, the shear acts to smear out the concentration distribution in the direction of the flow, enhancing the rate at which it spreads in that direction. The effect is named after the British fluid dynamicist G. I. Taylor. The canonical example is that of a simple diffusing species in uniformPoiseuille flow through a uniform circular pipe with no-fluxboundary conditions. We use z as an axial coordinate and r as the radialcoordinate, and assume axisymmetry. The pipe has radius a, andthe fluid velocity is: The concentration of the diffusing species is denoted c and itsdiffusivity is D. The concentration is assumed to be governed bythe linear advection–diffusion equation: