Data from: Hydrodynamic analysis of bioinspired vortical cross-step filtration by computational modelling

Research on the suspension-feeding apparatus of fishes has led recently to
the identification of novel filtration mechanisms involving vortices.
Structures inside fish mouths form a series of ‘backward-facing steps’ by
protruding medially into the mouth cavity. In paddlefish and basking shark
mouths, porous gill rakers lie inside ‘slots’ between the protruding
branchial arches. Vortical flows inside the slots of physical models have
been shown to be important for the filtration process, but the complex
flow patterns have not been visualized fully. Here we resolve the
three-dimensional hydrodynamics by computational fluid dynamics simulation
of a simplified mouth cavity including realistic flow dynamics at the
porous layer. We developed and validated a modelling protocol in ANSYS
Fluent software that combines a porous media model and permeability
direction vector mapping. We found that vortex shape and confinement to
the medial side of the gill rakers result from flow resistance by the
porous gill raker surfaces. Anteriorly directed vortical flow shears the
porous layer in the centre of slots. Flow patterns also indicate that slot
entrances should remain unblocked, except for the posterior-most slot.
This new modelling approach will enable future design exploration of
fish-inspired filters.