Stripe formation in horizontally oscillating granular suspensions
  We present the results of an experimental study of pattern formation in horizontally oscillating granular suspensions. Starting from a homogeneous state, the suspension turns into a striped pattern within a specific range of frequencies and amplitudes of oscillation. We observe an initial development of layered structures perpendicular to the vibration direction and a gradual coarsening of the stripes. However, both processes gradually slow down and eventually saturate. The probability distribution of the stripe width approaches a nonmonotonic steady-state form which can be approximated by a Poisson distribution. We observe similar structures in MD simulations of soft spherical particles coupled to the motion of the surrounding fluid. 
Robabeh Moosavi, Maniya Maleki, M. Reza Shaebani, J. C. Ruiz-Suarez,   Eric Clement
cond-mat.soft cond-mat.stat-mech