(a) Sketch of the particle clouds setup. (b) Growth rate of clouds having different particle sizes, hence corresponding to different settling velocities (the larger the faster) and Rouse numbers. Yellow hatchings are uncertainties on the reference growth rate of purely fluid, saltwater clouds. Dark and red symbols respectively correspond to experimental and numerical data. The black and white image is the superposition of all images from a single experiment without dye, while colored images are snapshots showing particles in white and dye in orange. Details about symbols can be found in [9].