中国物理B ›› 2026, Vol. 35 ›› Issue (7): 74701-074701.doi: 10.1088/1674-1056/ae40de

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Drift capability of swimming bacteria in shear flows

Fanglong Dang(党方龙)1, Wei Feng(冯伟)1, Xinlei Li(李欣蕾)2, Luo Hao(罗昊)1, Yanan Liu(刘亚楠)1, and Guangyin Jing(经光银)1,†   

  1. 1 School of Physics, Northwest University, Xi'an 7100127, China;
    2 College of Life Science, Northwest University, Xi'an 710069, China
  • 收稿日期:2025-12-11 修回日期:2026-01-20 接受日期:2026-02-03 发布日期:2026-07-10
  • 通讯作者: Guangyin Jing E-mail:jing@nwu.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 12174306, 12004308, W2421001, and 12474197), the Natural Science Basic Research Program of Shaanxi (Grant Nos. 2023-JC-JQ-02 and 2024JCZDXM-06), the Shaanxi Academy of Fundamental Sciences (Mathematics, Physics No. 23JSY024), and Shaanxi Province Science and Technology Rising Star Program (Grant No. 2025ZC-KJXX-51).

Drift capability of swimming bacteria in shear flows

Fanglong Dang(党方龙)1, Wei Feng(冯伟)1, Xinlei Li(李欣蕾)2, Luo Hao(罗昊)1, Yanan Liu(刘亚楠)1, and Guangyin Jing(经光银)1,†   

  1. 1 School of Physics, Northwest University, Xi'an 7100127, China;
    2 College of Life Science, Northwest University, Xi'an 710069, China
  • Received:2025-12-11 Revised:2026-01-20 Accepted:2026-02-03 Published:2026-07-10
  • Contact: Guangyin Jing E-mail:jing@nwu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 12174306, 12004308, W2421001, and 12474197), the Natural Science Basic Research Program of Shaanxi (Grant Nos. 2023-JC-JQ-02 and 2024JCZDXM-06), the Shaanxi Academy of Fundamental Sciences (Mathematics, Physics No. 23JSY024), and Shaanxi Province Science and Technology Rising Star Program (Grant No. 2025ZC-KJXX-51).

摘要: The ability of microorganisms to control their swimming direction is crucial for navigating complex flow environments at low Reynolds numbers. We study how swimming Escherichia coli generate transverse locomotion across streamlines, defined as drift swimming, i.e., perpendicular to the flow direction, resulting from the chiral coupling between their flagellar rotation and an imposed shear flow. The drift velocity increases linearly with shear rate at low shear and saturates at a maximum value comparable to the intrinsic swimming speed. This maximum drift grows monotonically as cells approach the channel wall and is strongly enhanced under geometric confinement. Reorientation dynamics reveal a marginally stable fixed point along the vorticity axis, with oscillations around it arising from thermal noise and body–flagellum misalignment. Wall-induced hydrodynamic constraints suppress these fluctuations and amplify the drift. Our results demonstrate an enhanced navigation capacity under extreme shear relevant to bacterial colonization in confined environments.

关键词: rheotaxis, bacterial swimming, shear flow, drift motion

Abstract: The ability of microorganisms to control their swimming direction is crucial for navigating complex flow environments at low Reynolds numbers. We study how swimming Escherichia coli generate transverse locomotion across streamlines, defined as drift swimming, i.e., perpendicular to the flow direction, resulting from the chiral coupling between their flagellar rotation and an imposed shear flow. The drift velocity increases linearly with shear rate at low shear and saturates at a maximum value comparable to the intrinsic swimming speed. This maximum drift grows monotonically as cells approach the channel wall and is strongly enhanced under geometric confinement. Reorientation dynamics reveal a marginally stable fixed point along the vorticity axis, with oscillations around it arising from thermal noise and body–flagellum misalignment. Wall-induced hydrodynamic constraints suppress these fluctuations and amplify the drift. Our results demonstrate an enhanced navigation capacity under extreme shear relevant to bacterial colonization in confined environments.

Key words: rheotaxis, bacterial swimming, shear flow, drift motion

中图分类号:  (Swimming microorganisms)

  • 47.63.Gd
47.63.-b (Biological fluid dynamics) 47.61.-k (Micro- and nano- scale flow phenomena) 47.90.+a (Other topics in fluid dynamics)