Diffusion of point-like particles in a two-dimensional channel of varying width is studied. The particles are driven by an arbitrary space dependent force. We construct a general recurrence procedure mapping the corresponding two-dimensional advection-diffusion equation onto the longitudinal coordinate x. Unlike the previous specific cases, the presented procedure enables us to find the one-dimensional description of the confined diffusion even for non-conservative (vortex) forces, e.g. caused by flowing solvent dragging the particles. We show that the result is again the generalized Fick-Jacobs equation. Despite of non existing scalar potential in the case of vortex forces, the effective one-dimensional scalar potential, as well as the corresponding quasi-equilibrium and the effective diffusion coefficient [Formula: see text] can be always found.
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http://dx.doi.org/10.1088/1361-648X/aac146 | DOI Listing |
J Math Biol
January 2025
School of Mathematics and Statistics, Northeast Normal University, 5268 Renmin Street, Changchun, 130024, Jilin, People's Republic of China.
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Aragon Institute of Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain.
ArXiv
October 2024
Department of Mechanical Engineering, University of Michigan, United States.
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View Article and Find Full Text PDFSci Rep
October 2024
Institute of Continuum Mechanics and Biomechanics, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058, Erlangen, Germany.
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