The transport of sediments by turbulent flows is commonly found in both nature and industry. Some examples are the transport of sand in deserts, rivers and oceans, sediment transport in channels, dredging lines and sewer systems, and pneumatic and hydraulic conveying of grains in food industry. For horizontal flows, there is usually the formation of a granular bed whose topmost layers are mobile and the bottom layers are static. Under certain conditions, the granular bed may deform, leading to the formation of ripples and dunes. This is a complex problem where the deformed bed disturbs the turbulent flow that has initially caused the deformation. Despite the scientific effort over the last decades to understand the problem, it is still far from being completely understood. This MSc thesis consists of an experimental investigation of three-dimensional dunes growing under turbulent flow conditions. For that, the morphodynamics of dunes will be evaluated from high-speed movies and numerical scripts written for the purpose of identifying lengths and velocities.
News published in Agência FAPESP Newsletter about the scholarship: