Elastic Convection in Vibrated Viscoplastic Fluids
  We observe a new type of behavior in a shear thinning yield stress fluid: freestanding convection rolls driven by vertical oscillation. The convection occurs without the constraint of container boundaries yet the diameter of the rolls is spontaneously selected for a wide range of parameters. The transition to the convecting state occurs without hysteresis when the amplitude of the plate acceleration exceeds a critical value. We find that a non-dimensional stress, the stress due to the inertia of the fluid normalized by the yield stress, governs the onset of the convective motion. 
Hayato Shiba, Jori Ruppert-Felsot, Yoshiki Takahashi, Yoshihiro   Murayama, Qi Ouyang, and Masaki Sano