BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Dispersion of active particles in steady and oscillatory flows - B
 ohan Wang\, China Institute of Water Resources and Hydropower Research
DTSTART:20251113T130000Z
DTEND:20251113T140000Z
UID:TALK240829@talks.cam.ac.uk
CONTACT:Anand Srinivasan
DESCRIPTION:Understanding the dispersion of active particles is crucial fo
 r predicting their macroscopic transport. While classical Taylor dispersio
 n explains solute spreading in shear flows\, active suspensions introduce 
 additional complexity due to the coupling between motility and external fl
 ow. In this talk\, I will first compare several continuum models—the Smo
 luchowski\, Pedley–Kessler (PK)\, and Generalised Taylor Dispersion (GTD
 ) models—using a gyrotactic swimmer suspension with buoyancy–flow coup
 ling effect in a vertical pipe as a benchmark. I will then present a new S
 moluchowski-based dispersion framework for oscillatory flows\, in which th
 e PK and GTD models become either inefficient at low frequencies or invali
 d at high frequencies. To address this\, we introduce two time variables t
 o capture both effective and oscillatory dynamics without assuming time-sc
 ale separation\, thereby greatly simplifying the application of Aris' meth
 od of moments. The framework shows excellent agreement with Brownian dynam
 ics simulations across the full frequency spectrum and reveals two distinc
 t dispersion regimes of active particles depending on the oscillation freq
 uency. Moreover\, the two time-variable framework can be extended to other
  oscillatory dispersion processes\, such as periodic variations in swimmin
 g speed and shape due to flagellar beating\, as well as systems involving 
 multiple oscillatory frequencies.
LOCATION:MR14\,  Centre for Mathematical Sciences\, Wilberforce Road\, Cam
 bridge
END:VEVENT
END:VCALENDAR