Dresden 2026 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 61: Brownian Motion and Anomalous Transport
DY 61.6: Vortrag
Freitag, 13. März 2026, 10:45–11:00, ZEU/0118
Advection-diffusion processes of Brownian particles in a long corrugated channel: mean first passage time approach — •Xiaohan Huang, Paolo Malgaretti, and Jens Harting — Helmholtz Institute Erlangen-Nürnberg for Renewable Energy, Cauerstr. 1, 91058 Erlangen, Germany
Transport of particles in porous media in micro- and mesoscopic scales is of interest in many applications, such as the catalytic transport and nanoparticles separations. In such scenarios, the time that a particle takes to reach a target for the first time, namely the mean first passage time (MFPT), represents a standard indicator. We model the advection-diffusion of a finite size particle in a diluted suspension through a corrugated channel of N varying cross sections elements. Under the fast transverse equilibrium and the slow longitudinal transport, we encode the geometric effect to an effective entropic potential via the Fick-Jacobs approximation [1]. Together with the lubrication approximation, the 2D equation is reduced to 1D, allowing us to solve the moments of MFPT. The resulting data collapse onto a master curve, enabling us to identify the relevant dimensionless numbers: the MFPT without advection and the particle-sensitive effective advection v. v is the average velocity of a particle in a single element, accounting for advection, geometry and particle-wall interactions. Thus, 1st and 2nd moment of MFPT are expressed as f(Pe), Pe=vNL/D [2]. The model predicts the particle transport in a long channel, enabling fast parameter studies in porous media design.[1] P. Malgaretti et al. Entropy 2023. [2] X.Huang et al. in preparation.
Keywords: Transport properties; Advection-diffusion processes; Porous media; First passage time