  Channels are fundamental building blocks from biophysics to soft robotics,
often used to transport or separate solutes. As solute particles inevitably
transverse between streamlines along the channel by molecular diffusion, the
effective diffusion of the solute along the channel is enhanced - an effect
known as Taylor dispersion. Here, we investigate how the Taylor dispersion
effect can be suppressed or enhanced in different settings. Specifically, we
study the impact of flow profile and active or pulsating channel walls on
Taylor dispersion. We derive closed analytic expressions for the effective
dispersion equation in all considered scenarios providing hands-on effective
dispersion parameters for a multitude of applications. In particular, we find
that active channel walls may lead to three regimes of dispersion: either
dispersion decrease by entropic slow down at small Peclet number, or dispersion
increase at large Peclet number dominated either by shuttle dispersion or by
Taylor dispersion. This improves our understanding of solute transport e.g. in
biological active systems such as blood flow and opens a number of
possibilities to control solute transport in artificial systems such as soft
robotics.
