EAGER: Sediment Transport in the Wake of a Marine HydroKinetic Turbine

海洋水动力能源是一种尚未开发的可再生能源，具有巨大的潜力。从河流、潮汐通道和洋流等自由流中回收能源最终可能会对美国的电力做出重大贡献，但我们目前缺乏对如何以环境安全的方式回收这种能源的了解。由于资源的高度集中性和大多数（如果不是全部）高能量密度场所的环境敏感性，MHK能源的成功回收关键取决于最紧迫的环境问题的答案。具体而言，我们还不了解MHK设备的运行如何改变当地的水流环境和由此产生的沉积物动力学，我们也没有方法来量化这些影响。涡轮机或其支撑结构的尾流对海底沉积物的重新分布可能会改变海底生态系统的特征。沉积物的再悬浮可能会重新引入原本从自由沉积物中沉淀出来的污染物，而涡轮机尾流中的动量可能会导致沉积增加。 为了使海洋流体动力学在美国和世界其他地区成为一种可行的能源，我们必须了解这些设备对环境的影响。在EAGER项目中，将在MHK涡轮机模型上进行实验室规模的演示实验，以模拟目前正在评估MHK能量回收的不同环境。一种新的两相粒子图像测速（PIV）技术开发的UMD将被用来量化的载体#64258;流体和泥沙颗粒的悬浮负荷动态。将使用河床剖面来评估局部侵蚀和沉积的变化。PI的长期目的是表征和量化海洋&地球&物理环境与MHK涡轮机尾流之间相互作用的两相流物理特性，具体为&：c.对沉积物再分配的兴趣。智力上的优点这项工作的智力上的优点在于非平衡沉积动力学的基本性质，这种非平衡沉积动力学是由于具有&高度湍流和涡度特征的复杂流而发生的。 首先，PI将在实验室规模的实验中量化MHK涡轮机近尾流对沉积物抬升和输运的影响，主要目标是产生演示数据，说明该设施和技术的能力和实用性。基于对相关fl通过这些实验获得的低物理学，PI将开始对缩放条件和建模的初步调查，这将允许创建由MHK #64258;ow #64257;elds引起的沉积物输运的新模型&&。更广泛的影响这项工作的更广泛的影响将扩展到教育和工业领域。拟议的研究将使MHK能源能够在广泛的潜在运营地点和条件下以公平、及时和有效的方式进行评估。因此，它可以为一种新的能源打开大门，这种能源可以迅速影响美国生产的可再生能源的比例，取代不可再生和污染性能源。

Marine HydroKinetic (MHK) energy is a largely undeveloped renewable energy source with great potential. Energy recovery from freestream flows such as rivers, tidal passages, and ocean currents may eventually make a significant contribution to U.S. power, but we currently lack understanding of how to recover this energy in an environmentally-safe way. Because of the highly concentrated nature of the resource and the environmental sensitivity of most, if not all, of the high-energy-density sites, successful recovery of MHK energy depends critically on finding answers to the most pressing environmental concerns. Specifically, we do not yet understand how the operation of MHK devices alters the local flow environment and resulting sediment dynamics, nor do we have the methods to quantify these effects. Redistribution of sea floor sediment by the wake of the turbine or its support structure could potentially change the character of the benthic ecosystem. Resuspension of sediment may reintroduce contaminants that had otherwise settled out of the freestream, and the momentum deficit in the wake of the turbine could lead to enhanced deposition. For marine hydrokinetics to become a viable energy resource in the U.S. and the rest of the world, we must understand the environmental effects of these devices.In this EAGER project, Laboratory-scale demonstration experiments will be performed on models of MHK turbines to model the different environments where MHK energy recovery is currently being evaluated. A novel two-phase particle image velocimetry (PIV) technique developed at UMD will be used to quantify the suspended load dynamics of both the carrier fluid and the sediment particles. Bed profiling will be used to assess changes in the local erosion and deposition. The long-term of the PIs is to characterize and quantify the two-phase flow-physics of the interaction between the sea floor geophysical environment and the wake of an MHK turbine, with a specific interest in the redistribution of sediment.Intellectual MeritThe intellectual merit of this work lies in the fundamental nature of non-equilibrium sediment dynamics that occur as a result of a complex flow characterized by high levels of turbulence and vorticity. First, the PIs will quantify the effect of the near wake of a MHK turbine on sediment uplift and transport in laboratory-scale experiments, primarily with the goal to produce demonstration data that illustrates the capabilities and utility of the facility and techniques. Based on the enhanced understanding of the relevant flow-physics gained through these experiments, the PIs will start the initial investigations of the scaling conditions and modeling that will allow the creation of new models for sediment transport induced by MHK flow fields.Broader ImpactsThe broader impacts of this work will extend to both the educational and industrial arenas. The proposed research will enable MHK energy to be assessed in a fair, timely and efficient manner, over a broad range of potential operational sites and conditions. Thus, it could open the doors to a new source that could quickly impact the percentage of renewable energy produced in the United States, displacing non-renewable and polluting sources.