“…The flow and transport processes involved are characterised by complex interactions between the porous medium and the free flow, including the two-way exchange of mass, momentum and energy across the interface (Breugem, Boersma & Uittenbogaard 2006;Manes, Poggi & Ridolfi 2011;Fang et al 2018;Suga, Okazaki & Kuwata 2020). Understanding the transport behaviour at the permeable interface is a non-trivial challenge, which involves a wide range of properties of the porous medium, such as permeability (Suga, Nakagawa & Kaneda 2017;Voermans, Ghisalberti & Ivey 2017;Rosti, Brandt & Pinelli 2018), surface roughness ) and pore geometry (Suga et al 2020;Shen, Yuan & Phanikumar 2020;McCorquodale & Munro 2021;Xu et al 2021). The early works have (Finnigan 2000;Jiménez et al 2001;Breugem et al 2006) established a framework for the coupling dynamics across the interface, which can be summarized as competing mechanisms in the flow: the formation of wall-attached eddies and the disruption by shear layer instabilities.…”