This session is focused on the presentation of theoretical and applied works involving the resolution of fluid flow and/or mass transport problems in non-homogeneous media and systems. These non-homogeneities frequently manifest through scale jumps or phase changes, occurring primarily at a micrometric scale. Key examples include porous media, hydraulic fractures, microdroplets, microemulsions, and environments with heterogeneities induced by the accumulation of electrical charges in solution. Intrinsic characteristics of these physical systems include laminar fluid flow regimes, or very low Reynolds numbers, and, in the case of mass transport, conditions dominated by high Péclet numbers. These scenarios are characteristic of a wide variety of contexts and applications, such as paper-based microfluidics, enhanced oil recovery, contaminant migration in soils and aquifers, reactant transport in mineral matrices, transport in artificial biological media, transport of biomolecules in micro- and nanostructured spaces, and lubrication flows [1],[2],[3],[4]. Ultimately, this session seeks to gather contributions from both theoretical and applied perspectives, promoting an interdisciplinary exchange between academic research and technological challenges in these diverse areas. REFERENCES [1] N. Franck, C. L. A. Berli, P. A. Kler, and R. Urteaga, “Multiphysics approach for fluid and charge transport in paper-based microfluidics”, Microfluidics and Nanofluidics, Vol. 26, (2022). [2] L. Bessone, P. Gamazo, M. Dentz, M. Storti, and J. Ramos, “GPU implementation of Explicit and Implicit Eulerian methods with TVD schemes for solving 2D solute transport in heterogeneous flows”, Computational Geosciences, Vol. 26, pp. 517-543, (2022). [3] G. S. Gerlero, A. R. Valdez, R. Urteaga, and P. A. Kler, “Validity of Capillary Imbibition Models in Paper-Based Microfluidic Applications”, Transport in Porous Media, (2022). [4] F. Zabaleta, S. Marquez Damian, and F. A. Bombardelli, “A novel three-phase mixture approach for the numerical modeling of self-aerated flows”, Computer Methods in Applied Mechanics and Engineering, Vol. 408, (2023).