Skip to Main content Skip to Navigation
Journal articles

Collisions and rebounds of chemically active droplets

Abstract : Active droplets swim as a result of the nonlinear advective coupling of the distribution of chemical species they consume or release with the Marangoni flows created by their non-uniform surface distribution. Most existing models focus on the self-propulsion of a single droplet in an unbounded fluid, which arises when diffusion is slow enough (i.e. beyond a critical Péclet number, Pec). Despite its experimental relevance, the coupled dynamics of multiple droplets and/or collision with a wall remains mostly unexplored. Using a novel approach based on a moving fitted bispherical grid, the fully-coupled nonlinear dynamics of the chemical solute and flow fields are solved here to charac-terise in detail the axisymmetric collision of an active droplet with a rigid wall (or with a second droplet). The dynamics is strikingly different depending on the convective-to-diffusive transport ratio , Pe: near the self-propulsion threshold (moderate Pe), the rebound dynamics are set by chemical interactions and are well captured by asymptotic analysis; in contrast, for larger Pe, a complex and nonlinear combination of hydrodynamic and chemical effects set the detailed dynamics, including a closer approach to the wall and a velocity plateau shortly after the rebound of the droplet. The rebound characteristics, i.e. minimum distance and duration, are finally fully characterised in terms of Pe.
Document type :
Journal articles
Complete list of metadata

Cited literature [67 references]  Display  Hide  Download
Contributor : Sébastien Michelin Connect in order to contact the contributor
Submitted on : Wednesday, April 8, 2020 - 12:38:53 PM
Last modification on : Monday, July 27, 2020 - 1:00:05 PM


Files produced by the author(s)




Kevin Lippera, Matvey Morozov, Michael Benzaquen, Sébastien Michelin. Collisions and rebounds of chemically active droplets. Journal of Fluid Mechanics, Cambridge University Press (CUP), 2020, 886, ⟨10.1017/jfm.2019.1055⟩. ⟨hal-02536797⟩



Record views


Files downloads