Filtration design for organic particle collection from oceanic currents

Unlike conventional industrial filtration designs-which usually rely on dead-end filtering or k-type surface roughness- biological systems employ fundamentally different strategies. Certain suspension-feeding fish, such as paddlefish and basking sharks, use cross-flow filtration, trapping particles within recirculation zones formed by backward-facing steps (Sanderson et al., 2016). Others, like manta rays, utilize a ricochet filtration mechanism, where particles are repeatedly deflected by wing-like structures, preventing clogging of filter pores (Divi et al., 2018; Mao et al., 2024).

In this study, we combine experimental and computational methods to investigate these natural filtration mechanisms and translate them into bioinspired designs for enhanced particle separation. The resulting structures effectively filter particles ranging from 10 to 1000 μm across varying freestream velocities (). These designs leverage the underlying principles of cross-flow (generation of recirculating regions) and ricochet filtration (directional pressure gradients), both of which serve to amplify velocity gradients, maximize the Stokes number, and promote efficient phase separation.

References

1. Divi, R. V., Strother, J. A., & Paig-Tran, E. W. M. (2018). Manta rays feed using ricochet separation, a novel nonclogging filtration mechanism. Science Advances, 4(9). https://doi.org/10.1126/sciadv.aat9533

2. Mao, X., Bischofberger, I., & Hosoi, A. E. (2024). Permeability–selectivity trade-off for a universal leaky channel inspired by mobula filters. Proceedings of the National Academy of Sciences, 121(50). https://doi.org/10.1073/pnas.2410018121

3. Sanderson, S. L., Roberts, E., Lineburg, J., & Brooks, H. (2016). Fish mouths as engineering structures for vortical cross-step filtration. Nature Communications, 7(1), 11092. https://doi.org/10.1038/ncomms11092