ONGOING PROJECTS

Nonlinear Dynamics of Largely-deformed Viscous Fluid

Shin-ichiro Nagahiro and Yoshinori Hayakawa, August 2008

A simple model is proposed for the buckling and coiling instability of a viscous gfluid ropeh falling on a plane. By regarding a fluid rope as a one-dimensional flow, this model accounts for only the axial and shared viscous forces. Our model successfully reproduces several experiments with no adjustable parameters, such as the existence of three distinct coiling regimes reported in the paper by Maleki et al. [Phys. Rev. Lett. 93, 214502 (2004)]. Our model allows for the discussion of unsteady motion. An expression for the critical fall height at which the coiling frequency changes from a decrease to increase was phenomenologically derived. It was found that the coil-uncoil transition shows remarkable hysteresis only for weak gravity condition.

[1] Bending-filament model for the buckling and coiling instability of a viscous fluid rope,  Shin-ichiro Nagahiro and Yoshinori Hayakawa, Physical Review E 78, 025302(R) (2008) .

[2] Model for Coiling and Meandering Instability of Viscous Threads, Shin-ichiro Nagahiro and Yoshinori Hayakawa, Journal of Physical Society of Japan 78, 124402 (2009).


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