This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.Microfluidic bumper arrays are increasingly being used for the size-based sorting of particle
suspensions. The separation mechanism is based on the interaction between a spatially periodic array of obstacles
and the suspended particles as they are driven through the obstacle lattice either by volume forces or
by the Stokesian drag of the surrounding fluid. By this mechanism, a focused stream of suspended particles
of different sizes entering the lattice splits into different currents, each entraining assigned ranges of particle
dimensions, and each characterized by a specific angle with respect to the main device axis. In this work, we
build up on recent results stemming from macrotransport process theory to derive a closed-form solution for
the steady-state distribution of advecting-diffusing particles in the presence of anisotropic dispersion, which
typically characterizes large-scale behavior of particle motion through the periodic lattice. Attention is focused
on separation resolution, that ultimately controls the feasibility of the separation in specific applications
