Fish – bubble analogy

We have recently shown that the escape of fish is analogous to that of bubbles[1]. Indeed, the fish outflow (fish/s) is well fitted by the Beverloo law used for bubbles in a similar situation by Bertho et al.[2]. We have modelled the fish as surrounded by a cognitive bubble that governs their outflow statistics.

We would like to further explore this analogy and its limitations. To do so, we need to perform bubble evacuation in the laboratory by varying some parameters such as the size of the opening, the evacuation stress and the interactions between bubbles. In this way, we can analyse the statistics of exit time intervals in the same way as we did for fish and see if the model proposed for fish is valid for bubbles. If time permits, we can also test a second experiment with two nearby openings. This experiment is currently being carried out with fish and can therefore be compared with bubbles. On the fish side, we can expect the symmetry of the experimental system to be broken if the fish evacuate in groups through one or other of the two openings. The question is also open on the side of the bubbles, will the bubbles exit identically through the two openings, knowing that they are very close?

The trainee will have to finalise the experimental set-up and carry out the different experiments with the bubbles. He/she will then analyse the images obtained and participate in the modelling.

References :

[1] Larrieu, R., Moreau, P., Graff, C., Peyla, P., & Dupont, A. (2022). Forcing a fish school through a bottleneck: a smooth evacuation. arXiv preprint arXiv:2212.12514
[2] Bertho, Y., Becco, C., & Vandewalle, N. (2006). Dense bubble flow in a silo: An unusual flow of a dispersed medium. Physical Review E, 73(5), 056309.