  Under low-Reynolds-number conditions, dynamics of convection and diffusion
are usually considered separately because their dominant spatial and temporal
scales are different, but cooperative effects of convection and diffusion can
cause diffusion enhancement [Koyano et al., Phys. Rev. E, 102, 033109 (2020)].
In this study, such cooperative effects are investigated in detail. Numerical
simulations based on the convection-diffusion equation revealed that
anisotropic diffusion and net shift as well as diffusion enhancement occur
under a reciprocal flow. Such anomalous diffusion and transport are
theoretically derived by the analyses of the Langevin dynamics.
