The course of a peritrichous bacterium such as E. coli crucially depends on
the level of synchronization and self-organization of several rotating
flagella. However, the rotation of each flagellum generates counter body
movements which in turn affect the flagellar dynamics. Using a detailed
numerical model of an E. coli, we demonstrate that flagellar entanglement,
besides fluid flow relative to the moving body, dramatically changes the
dynamics of flagella from that compared to anchored flagella. In particular,
bundle formation occurs through a zipping motion in a remarkably rapid time,
affected little by initial flagellar orientation. A simplified analytical model
supports our observations. Finally, we illustrate how entanglement,
hydrodynamic interactions, and body movement contribute to zipping and
bundling.Comment: 5 page
