  It has been shown that a nanoliter chamber separated by a wall of asymmetric
obstacles can lead to an inhomogeneous distribution of self-propelled
microorganisms. Although it is well established that this rectification effect
arises from the interaction between the swimmers and the non-centrosymmetric
pillars, here we demonstrate numerically that its efficiency is strongly
dependent on the detailed dynamics of the individual microorganism. In
particular, for the case of run-and-tumble dynamics, the distribution of run
lengths, the rotational diffusion and the partial preservation of run
orientation memory through a tumble are important factors when computing the
rectification efficiency. In addition, we optimize the geometrical dimensions
of the asymmetric pillars in order to maximize the swimmer concentration and we
illustrate how it can be used for sorting by swimming strategy in a long array
of parallel obstacles.
