Collaborative Research: Sediment Transport in Oscillating Turbulent Boundary Layers

0351667/0351443A将对湍流振荡边界层流中的泥沙输运机制进行紧密结合的数值和实验研究。这项研究将通过重点了解运输过程的微观机制来补充和扩展现有的知识库。这个想法是将过去十年工程界发展起来的研究湍流颗粒流动的技术应用到手头的问题上。在数值方面，这将通过组合欧拉/拉格朗日直接数值模拟和使用浸没边界技术的流体/颗粒运动的大涡模拟和流动泥沙床的双流体碰撞壁模型来实现。流体相的数值模拟将与颗粒相的基于拉格朗日的方法相结合，以在单个颗粒水平上研究泥沙夹带机制的行为以及颗粒对流体相湍流的修正。在实验中，我们实验室首创的两相粒子图像测速技术的最新创新将被应用于提供对振荡边界层水道内的流体和沉积物相的详细、瞬时、空间分辨率的测量。挑战是使这些技术适应海洋中遇到的尺度和参数范围。广泛的影响大陆架上的沉积物运动是海岸研究中的一个重要课题。应用的例子包括颗粒有机物和人造污染物的运输；预测水柱的光学性质；评估考古文物的埋藏率；预测沿海洪水和侵蚀；评估商业渔业的栖息地；以及污水处理厂和冷却系统的进水口和排水口的设计。一个具有广泛潜在应用的最先进的实验设施的开发将打开其他领域的研究可能性，并促进进一步的跨学科合作。结合最先进的数值技术来求解两相壁面湍流流动的数值工具的开发将使我们能够对这一过程有新的认识。在这个项目中培训的研究生和博士后将在一个令人兴奋的跨学科环境中接触到先进的数值和实验技术。最后，模型和实验的输出将包括在调查人员的教学档案袋中。

0351667/0351443A closely integrated numerical and experimental investigation of sediment transport mechanisms within turbulent oscillatory boundary layer flows will be conducted. The study will complement and extend the existing knowledge base through a focus on understanding the micromechanics of the transport process. The idea is to apply to the problem at hand techniques that have been developed during the last decade in the engineering community to study turbulent particle laden flows. On the numerical side, this will be done through the novel use of a combined Eulerian/Lagrangian Direct Numerical Simulation and Large Eddy Simulation of the fluid/particle motion using an immersed boundary technique and a two-fluid collisional wall model for the mobile sediment bed. The numerical modeling for the fluid phase will be done in conjunction with a Lagrangian based approach for the particulate phase to study the behavior, at the individual particle level, of the sediment entrainment mechanisms as well as the modification induced by the particles on the turbulence of the fluid phase. For the experiments, recent innovations in two-phase Particle Image Velocimetry techniques, pioneered in our laboratory, will be applied to provide detailed, instantaneous, spatially resolved measurements of both the fluid and the sediment phase within an oscillatory boundary layer water channel. The challenge is to adapt these techniques to the scales and parameter range encountered in the ocean.Broader ImpactsThe motion of sediments over the continental shelf is an important topic in coastal studies. Examples of applications include transport of particulate organic matter and man-made contaminants; prediction of the optical properties of the water column; evaluation of burial rates of archaeological artifacts; prediction of coastal flooding and erosion; evaluation of habitat of commercial fisheries; and the design of intakes and outfalls of sewage treatment plant and cooling systems. The development of a state-of-the-art experimental facility with a wide range of potential applications will open research possibilities in other areas, and foster further interdisciplinary collaborations. The development of a numerical tool incorporating the most advanced numerical techniques for the solution of two-phase wall-bounded turbulent flows will allow new insight of the process. The graduate students and a post-doc trained in this project will be exposed to advanced numerical and experimental techniques, within an exciting interdisciplinary environment. Finally, The output from model and experiments will be included in the teaching portfolio of the investigators.