Modifications of the turbulent structure in a bubbly boundary layer

In recent years, evidence is accumulating on the fact that dispersing modest quantities of particles or bubbles in turbulent environments may lead to substantial modifications of the large scales of the flow, as well as of its global parameters. Interaction with the large-scale structures occurs even when the characteristic dimension of the dispersed phase lies below the smallest turbulent wavelength, and may be understood in terms of the significant inhomogeneities of the instantaneous concentration field associated to the preferential accumulation in the cores of vortical structures (for the case of bubbles). In turn, such large fluctuations in the bubble concentration dramatically modify the bulk properties of the underlying flow.