Multiphase flows play a central role in a broad range of natural and engineered processes, such as nutrient cycles and contaminant remediation in soils, and geological storage of carbon dioxide and hydrogen in deep reservoirs. Understanding multiphase systems across scales is therefore fundamental for water resources management as well energy and climate concerns.

The presence of multiple fluid phases enhances heterogeneity at the level of flow, mixing, and reaction in structurally heterogeneous media. This impacts the transport of dissolved substances and fundamentally changes mixing patterns and effective reaction rates, posing major challenges for predictive modeling. Recent theoretical and experimental advances provide unprecedented insights into the pore-scale mechanisms governing these processes and open new opportunities to tackle these challenges.

This session aims to bring together researchers working on fundamental and applied aspects of flow, transport, mixing, and reaction in multi-phase systems across scales. In particular, we encourage submissions relating to experimental, numerical, and theoretical contributions pertaining to the following topics:

- Impact of medium heterogeneity on multiphase flow, from the pore to the continuum scale.
- Impact of multiphase flow patterns on mixing and reaction rates across scales in heterogeneous media.
- Biogeochemical processes in multiphase systems.
- Applications to vadose zone hydrology and geological storage.