Estudo da velocidade de queda e do início do movimento das partículas de borracha e areia

Abstract

The proper design of a dam depends on a set of studies and strategic decision-making, both strongly impacted by local constraints. Due to the fact that this type of enterprise usually consist in a large facility, several aspects of engineering should be considered in your project, which include water availability, local geology and even the type and amount of sediment carried by the river. The ladder aspect, which is directly associated to the accumulation of sediments along the reservoirs and its life spam, has been systematically neglected over the years in Brazil. The sedimentation process, a natural phenomenon to be expected whenever there is a decrease of water speed in river by the presence of the dam, causes a reduction in the storage and regularization capacity of the reservoirs. In some cases, as in hydroelectric plants, there is a gradual decrease in the capacity for generating energy, strongly affecting the national electricity system. The common sense applied by most studies consist in evaluating the sedimentation process with theoretical sediment transport equations, which invariably presents approximate results, that can be unreliable at times. In this context, the prediction and determination of the magnitude of the sedimentation impact is still an open problem that lacks investments and intellectual capital to be proper handled. The use of physical models with moving bed represents one of the alternatives used as counterpart, mainly in the analysis of the interaction between the flow, the affluent sediments and hydraulic structures. The sediment transport by the bed is simulated by applying diverse grain material and the flow estimation is made similar to the on-site flow regime. In other words, the material and processes used in these physical models are adjusted to mimic the real conditions of the study sites, in regards to the geometrical, kinematic or dynamic similarities of the flow process, as well as sediment transport. Traditionally, high density, organic materials are used to simulate affluent sediments, but it is important to notice that these organic materials are difficult to obtain and they are subject to decomposing over time. Nonetheless, the use of synthetic low cost materials can represent and viable alternative to be study in these physical models. Regarding the facts presented above, this thesis will show the results of the use of ground tire rubber grain as a viable alternative to be used in physical models, to mimic the natural behavior and characteristic of sand grain sediment, a material present in a high proportion of the transport and sediment deposition along reservoir