The study looked at how sand dunes move in rivers by conducting experiments in a closed channel. They found that the movement of sediment in the dunes follows a pattern, with some parts moving faster than others. The researchers also observed different types of oscillations in the sediment movement caused by the flow of water. By studying these patterns, they were able to predict how sediment moves over time. This information can be useful for understanding how sand dunes form and change in rivers, as well as for measuring how much sediment is being carried by the water.