Structurization and restructurization of a homogeneous suspension in a standing wave field

The process of formation of a spatially ordered fine structure in an originally uniform suspension of small-size particles in the field of two-dimensional standing surface gravity waves in a rectangular reservoir oscillating in the vertical direction is for the first time recorded in experiments. The parameters of structured regions are determined in reservoirs with both separate vortical ripples and their groups and with rough sandy and smooth regions of the bottom for the first and second wave modes. It is established that isolated structured regions are formed near the bottom or the free surface and gradually fill the fluid throughout its entire thickness. Minimum scales of the structures are on the Stokesian range, while maximum scales are determined by the geometry and the energy of the main flow. In all experiments performed the structurization was conserved during the entire interval of wave motion of the suspension and vanished during a few minutes after the parametric excitation of the waves has been stopped.