Dispersion of active particles in steady and oscillatory flows

Add to your list(s) Download to your calendar using vCal

• Bohan Wang, China Institute of Water Resources and Hydropower Research
• Thursday 13 November 2025, 13:00-14:00
• MR14, Centre for Mathematical Sciences, Wilberforce Road, Cambridge.

If you have a question about this talk, please contact Anand Srinivasan.

Understanding the dispersion of active particles is crucial for predicting their macroscopic transport. While classical Taylor dispersion explains solute spreading in shear flows, active suspensions introduce additional complexity due to the coupling between motility and external flow. In this talk, I will first compare several continuum models—the Smoluchowski, Pedley–Kessler (PK), and Generalised Taylor Dispersion (GTD) models—using a gyrotactic swimmer suspension with buoyancy–flow coupling effect in a vertical pipe as a benchmark. I will then present a new Smoluchowski-based dispersion framework for oscillatory flows, in which the PK and GTD models become either inefficient at low frequencies or invalid at high frequencies. To address this, we introduce two time variables to capture both effective and oscillatory dynamics without assuming time-scale separation, thereby greatly simplifying the application of Aris’ method of moments. The framework shows excellent agreement with Brownian dynamics simulations across the full frequency spectrum and reveals two distinct dispersion regimes of active particles depending on the oscillation frequency. Moreover, the two time-variable framework can be extended to other oscillatory dispersion processes, such as periodic variations in swimming speed and shape due to flagellar beating, as well as systems involving multiple oscillatory frequencies.

This talk is part of the DAMTP BioLunch series.

This talk is included in these lists:

• All CMS events
• BioLunch
• CMS Events
• CamBridgeSens
• Cambridge talks
• DAMTP BioLunch
• DAMTP info aggregator
• Interested Talks
• Life Science Interface Seminars
• MR14, Centre for Mathematical Sciences, Wilberforce Road, Cambridge
• Trust & Technology Initiative - interesting events
• bld31
• yk449

Note that ex-directory lists are not shown.