Tumbling of a Brownian particle in an extensional flow
  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. 
Emmanuel Lance Christopher VI Medillo Plan and Dario Vincenzi
physics.flu-dyn nlin.CD