School of Mechanical, Electrical and Manufacturing Engineering


12 December 2019

Hydrodynamics of fish swimming

Presented By Prof Christophe Eloy, Ecole Centrale de Marseille
  • 1.00 pm - 2.00 pm
  • TW.1.14, Wolfson Building

About this event



Fish swimming is a fascinating example of fluid-structure interactions. It involves three dimensional flows with complex vortex structures coupled with a flexible, internally-actuated body. In addition to its academic interest, fish swimming also serves as a source of inspiration for biomimetic autonomous vehicles or new propeller designs.


During this seminar, I will address two questions related to fish swimming:

- How to measure the efficiency of fish swimming?

- What are the effects of hydrodynamic interactions in a fish school?


Efficiency of fish swimming. Several definitions of fish swimming efficiency have been proposed in the literature. Which one should be used? As I will show during this seminar, the choice of a particular formulation of efficiency is closely linked to a goal or a task to be performed. It is thus not surprising that efficiency has different meanings in the evolutionary perspective of natural selection or in the design of a bio-inspired vessel.


Hydrodynamics of fish schooling. In a fish school, the group coordinates with simple rules of attraction and alignment between neighbours. But what is the role played by the fluid flow in this coordination? To address this question, we have developed a model that simulates the hydrodynamic interactions between hundreds of fish in a far-field approximation. This model has allowed us to evidence a surprising role of hydrodynamic interactions: fish spend less energy when swimming in school because they benefit, on average, from a “hydrodynamic drafting” effect. Hydrodynamic interactions also induce a noise and can yield a new arrangement of individuals on curved trajectories.



Christophe Eloy is a Professor in Mechanical Engineering at Ecole Centrale de Marseille, and an affiliate of the Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE). Prof. Eloy is a mathematical modeler who has brought his background in physics, math, and fluid mechanics to address a number of basic biological questions ranging from swimming by micro-organisms and by fish, hydrodynamic interactions in fish schools, and tree architecture.


Liguo Zhao

Wolfson School of Mechanical, Electrical and Manufacturing Engineering