Collaborative Research: SGER - Enhanced Sediment Transport due to Transient Wave Loads

翻译后摘要：拟议的研究的目的是调查的问题，由于瞬态波荷载的结果，建立超孔隙压力的沉积物流动性增强。 这一问题是了解风暴潮和海啸期间泥沙输运和冲刷的基础。 目前，大多数泥沙输移模型都将泥沙通量与平床准恒定流中水平力与垂直力的比值--Shield参数联系起来。 然而，在波谷（波峰）处存在向上（向下）的渗流，这可以显著地改变作用在土颗粒上的净垂直力。 此外，当地的河床坡度也影响泥沙的流动性。 因此，在拟议的工作中，泥沙输运率的孔隙压力梯度，颗粒密度和粒度，床坡度，床剪切应力的基本依赖性将通过数值模拟和实验模拟系统地检查。 将开发一个完全耦合流体、土壤和泥沙输运模型的数值模型，以预测风暴潮或海啸引起的泥沙输运和冲刷。 实验室研究将在夏威夷大学水力学实验室的小水槽中进行，以确定沉积物侵蚀率的经验关系。 该水槽具有透明的侧壁和透明的底部，适合详细的流动可视化和泥沙输运动力学的测量，并配备了一个泵，可以产生不同流速的水平流。通过小型水槽，可以轻松快速地配置不同的水流条件和地形配置。 应该强调的是，这个实验不适合，也没有必要，大型波浪水槽（如在俄勒冈州立大学）;在UH的小水槽是完美的这套实验做系统的，受控的研究。 拟议的研究是根本的，以提高对增强泥沙输运的理解，由于瞬态波载荷，这是至关重要的风暴潮和海啸引起的泥沙输运和冲刷的预测。 拟议的研究还有望改善未来的设计和改造指南，城市规划建议，最重要的是，减灾战略。 为了扩大影响，调查人员将把研究教育和外联活动纳入其中，包括教育社区了解风暴潮和海啸的危险和灾害规划战略。

Abstract:The objective of the proposed research is to investigate the problem of enhanced sediment mobility due to buildup of excess pore pressure as a result of transient wave loads. This problem is fundamental to the understanding of sediment transport and scour during storm surge and tsunami. Currently, most sediment transport models relate the sediment flux with Shield's parameter, which is the ratio of horizontal force to vertical force in a quasi-steady flow over a flat bed. However, there is an upward (downward) seepage at the trough (crest), which can significantly alter the net vertical force acting on the soil particle. In addition, the local bed slope also affects sediment mobility. Thus, in the proposed work, the fundamental dependence of sediment transport rate on the pore pressure gradient, particle density and grain size, bed slope, and bed shear stress will be systematically examined via numerical and experimental simulations. A numerical model which fully couples the fluid, soil, and sediment transport models will be developed to predict storm surge or tsunami-induced sediment transport and scour. Laboratory studies will be conducted at the small flume in the hydraulics lab at the University of Hawaii to determine the empirical relationship for the sediment erosion rate. The flume has transparent sidewalls and transparent bottom which are suitable for detailed flow visualization and measurement of sediment transport dynamics, and is equipped with a pump that can generate horizontal flow at different flow rates. With the small flume, different flow conditions and topographical configurations can be configured easily and quickly. It should be emphasized that this experiment is not suited, and not necessary, for large wave tanks (such as the ones in OSU); the small flume at UH is perfect for this set of experiment to do systematic, controlled studies. The proposed research is fundamental to improving the understanding of enhanced sediment transport due to transient wave loads, which is critical to the prediction of storm surge and tsunami-induced sediment transport and scour. The proposed research is also expected to improve future design and retrofit guidelines, urban planning recommendations, and most importantly, disaster mitigation strategies. To broaden the impact, the investigators will incorporate into the research education and outreach activities, including educating the community about the dangers and disaster planning strategies for storm surge and tsunami.