Barge dumping of rubble in deep water

When a load of coarse material is dumped from a barge in deep water, it descends in the water body as an irregularly shaped particle cloud, which is called a suspension thermal. As such a thermal keeps sinking it slows down and undergoes a transition to a smooth, bowl-shaped cluster. An important difference betweeen these two flow regimes is that in the thermal stage the fluid inside the cloud moves in unison with the particles, while it remains nearly motionless in the cluster stage as the particles fall through it. In this paper results of experiments on clusters are presented, and a description of the flow is proposed which covers both the thermal and the cluster stages, i.e. the entire range of flows which are of interest for barge dumping.