  The phenomenon of tumbling of microscopic objects is commonly associated with
shear flows. We address the question of whether tumbling can also occur in
stretching-dominated flows. To answer this, we study the dynamics of a
semi-flexible trumbbell in a planar extensional velocity field. We show that
the trumbbell undergoes a random tumbling-through-folding motion. The
probability distribution of long tumbling times is exponential with a time
scale exponentially increasing with the Weissenberg number.
