Career: Advanced Numerical Modeling of Bridge Foundation Scour

摘要9875691该职业奖的提议是出于对解决桥墩和桥台冲刷问题的综合研究策略的需要，桥墩和桥台冲刷是最近严重洪水期间破坏国家交通基础设施的桥梁故障的主要原因。 由于这个问题的巨大复杂性，这样的策略是有效的，它必须结合现场和实验室实验与三维计算建模。 这项工作的目的是开发一个先进的计算流体动力学模型相结合的最新进展，数值模拟和湍流模拟的复杂，三维流动的一种新的方法来模拟泥沙输运过程，导致冲刷。 数值方法将依赖于非定常三维雷诺平均纳维尔-斯托克斯（RANS）方程，该方程采用先进的湍流模型封闭，可解决近壁流问题，考虑湍流各向异性，并可模拟床面粗糙度。 这种水平的湍流模拟对于再现驱动冲刷过程的基础诱导大尺度漩涡的结构和强度至关重要。 一个耦合拉格朗日/欧拉方法将被开发用于模拟泥沙颗粒的运输和模拟冲刷的时间发展。 高效的数值方法，具有多重网格加速和预处理策略，将被用来解决时间相关的控制方程。 现有的实验室实验数据将用于校准和验证的数值模型。 这项研究将导致一个先进的计算框架，可用于提高我们的理解的复杂机制，诱导冲刷在现场的详细程度，以前无法访问的现场和实验室实验。 数值模型与实验研究相结合，将有助于评估桥梁设计的冲刷敏感性和冲刷对策的发展，是基于对流动物理的深入了解。 因此，这项工作可能会对目前的最新技术产生重大影响，目前的最新技术几乎完全依赖于来自小规模实验室测量的经验相关性。 此外，数值模型将有助于指导未来的改进实验，澄清的问题，如缩放的小规模实验的结果，全尺寸条件下的效果，冲刷的时间发展到平衡。 该职业计划的教育贡献将包括以下内容：i）计算流体动力学和水力学领域的土木和环境工程师新课程; ii）直接参与研究的本科生项目; iii）不可压缩湍流数值模拟的研究生级教科书。

Abstract9875691The proposal for this CAREER award was motivated by the need for a comprehensive research strategy to address the problem of bridge pier and abutment scour, the leading cause of bridge failures that devastated the nation's transportation infrastructure during recent severe floods. Due to the enormous complexity of this problem, for such a strategy to be effective it must integrate field and laboratory experiments with three-dimensional computational modeling. It is the objective of this work to develop an advanced computational fluid dynamics model by combining the latest advancements in numerical and turbulence modeling of complex, three-dimensional flows with a novel approach for modeling the sediment transport processes that lead to scour. The numerical methodology will rely on the unsteady, three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations closed with advanced turbulence models, which resolve the near-wall flow, account for turbulence anisotropy, and can simulate bed roughness. Such level of turbulence modeling is essential for reproducing the structure and intensity of the foundation-induced, large-scale vortices that drive the scouring process. A coupled Lagrangian/Eulerian approach will be developed for modeling the transport of sediment particles and simulating the temporal development of scour. Efficient numerical methods, featuring multigrid acceleration and preconditioning strategies, will be used to solve the time-dependent governing equations. Data from existing laboratory experiments will be used to calibrate and validate the numerical model. This research will lead to an advanced computational framework that can be used to enhance our understanding of the complex mechanisms that induce scour in the field at a level of detail not previously accessible by field and laboratory experiments alone. The numerical model, employed in conjunction with experimental studies, will facilitate the evaluation of bridge designs for scour susceptibility and the development of scour countermeasures that are based on in-depth understanding of the flow physics. Therefore, this work could potentially have a significant impact on the current state-of-the-art, which relies almost exclusively on empirical correlations derived from small-scale laboratory measurements. Furthermore, the numerical model will help guide future improved experiments by clarifying issues such as the effect of scaling the results of small-scale experiments to full-scale conditions, and the time development of scour toward equilibrium. The educational contributions of this CAREER plan will include, among others, the following: i) a new curriculum for Civil and Environmental engineers in the area of computational fluid dynamics and hydraulics; ii) projects for directly involving undergraduates in research; and iii) a graduate-level textbook on the numerical simulation of incompressible turbulent flows.