Understanding particle transport and diffusion in active suspensions: a multiscale study

Courant Institute, NYU

For many micro-organisms the process of feeding results from the complex interplay between the Brownian diffusion of target particles and their transport generated by the flow field around the swimmer. Understanding particle transport in active suspensions involves considering a wide range of length scales: from the submicronic Brownian particles to the whole suspension composed of thousands if not millions of micro-swimmers. In this presentation, I will shortly introduce the tools developed during my Ph.D to simulate active suspensions at large scales (approx. 100,000 micro-swimmers), while preserving an accurate number of hydrodynamic interactions. I will also briefly present our recent developments to model Brownian suspensions. Finally, I will combine these tools to address the issue of particle transport in dilute and concentrated active suspensions. Comparisons with experimental data will be shown and the physical mechanism hidden behind the experimental results will be detailed.