  We consider the problem of an inextensible but flexible fiber advected by a
steady chaotic flow, and ask the simple question whether the fiber can
spontaneously knot itself. Using a 1D Cosserat model, a simple local viscous
drag model and discrete contact forces, we explore the probability of finding
knots at any given time when the fiber is interacting with the ABC class of
flows. The bending rigidity is shown to have a marginal effect compared to that
of increasing the fiber length. Complex knots are formed up to 11 crossings,
but some knots are more probable than others. The finite-time Lyapunov exponent
of the flow is shown to have a positive effect on the knot probability.
Finally, contact forces appear to be crucial since knotted configurations can
remain stable for times much longer than the turnover time of the flow,
something that is not observed when the fiber can freely cross itself.
