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DY: Fachverband Dynamik und Statistische Physik
DY 22: Poster: Statistical Physics
DY 22.12: Poster
Wednesday, March 19, 2025, 10:00–12:00, P3
Rarefied gas transport in a narrow channel induced by an asymmetric wall geometry — •Constantin Rein1, Klaus Kroy1, and Viktor Holubec2 — 1Brüderstr. 16, D-04103 Leipzig — 2V Holešovičkách 747/2, Praha 8, Czech Republic
Since the work of Knudsen on gas transport in a narrow channel, it is known that gases in the dilute limit, where the mean free path is larger than the characteristic length scale, behave different as compared to the well known finite density regime[1]. So-called Knudsen pumps use temperature differences along channel walls to induce gas particle transport along the channel[2]. Inspired by the working principle of our recently introduced active Brownian ratchet[3], we investigate numerically and analytically the gas transport phenomenon appearing in a narrow channel with specular walls, except for a diffusively reflecting triangle that protrudes into the channel from one of the walls. Despite the absence of a variation in the wall temperature, a flow emerges. It arises solely from an asymmetry of the incoming and outgoing orientational distribution. The magnitude, direction and flow pattern of the induced transport is discussed.
[1] Knudsen, M. Eine revision der Gleichgewichtsbedingung der Gase, Thermische Molekularströmung. Ann. Phys. 336,205*229 (1909). [2] Wang, X., Su, T., Zhang, W., Zhang, Z. & Zhang, S. Knudsen pumps: a review. Microsyst Nanoeng 6, 26 (2020). [3] Rein, C., Kolář, M., Kroy, K. & Holubec, V. Force-free and autonomous active Brownian ratchets(a). EPL 142, 31001 (2023).
Keywords: Knudsen pump; rarefied gas