NEESR: Tsunami Induced Coherent Structures and their Impact on our Coastal Infrastructure

在美国和其他太平洋沿岸国家，地震引发的海啸造成的破坏可能比地震地面运动造成的破坏和死亡要大得多。海啸研究的目标是拯救生命，减少经济损失。要做到这一点，我们必须开发足够的科学知识和适当的工程工具，以此为基础制定全面的海啸缓解计划，并将这一信息有效地传达给决策者、应急规划界和公众。这项工作的首要主题是阐明受湍流相干结构(TC)驱动或影响的影响我国沿海结构的复杂过程。我们将研究在多个强迫环境中壁面约束的TCS的作用。在海床附近，TCS可以显著增强沉积物的吸收和输送，导致极端的冲刷和基础设施故障。在水平面上，TCS可以表现为巨大的漩涡，通常与港口和港口的极端破坏有关。俄勒冈州立大学(OSU)将利用大浪水槽(LWF)进行广泛的实验，以研究TCS对近床过程的精细意义，如泥沙的动员和输送，以及海啸波盆地(TWB)，以表征由港口产生的大型水平TCS的完整水动力结构。这些观察结果将得到广泛的数字努力的支持。为了详细研究TCS的产生及其对由瞬变长波运动引起的泥沙悬浮的影响，我们将使用三维湍流分辨率模拟模型，网格分辨率为1 mm。与流动模型完全耦合的将是针对单个沉积物颗粒的离散单元模型，从而允许对海啸引起的输送进行颗粒分辨模拟。将LWF和TWB的结果与高分辨率的数值工具相结合，将允许对一般海啸问题的床层动员、冲刷和港墙作用力进行预测，包括平均“均匀”海啸流和由于TCS造成的非常局部化的、复杂的速度的组合强迫。拟议活动的更广泛影响是，通过评估海啸，最终减少海啸造成的生命和财产损失。在这里，我们采取双管齐下的方法，对公众进行教育，让他们了解海啸事件可能带来的危险。首先，一项针对沿海各州初中生和高中生的计划将与TWB提出的实验研究密切相关。学生们将制定一个港口海啸应对计划，并将在TWB实施和测试。其次，我们确定了几种方法，以加强将我们的智力努力转移给不同的利益相关者。我们的知识传授给工程从业者将取代2-3个关于港口设计、沉积物冲刷和沉积物液化的网络研讨会。这些网络研讨会将提供关于现有设计做法和获得的新知识的信息。实践者将获得专业发展学分，课程将被记录在NEESHub上，以备将来使用。

The destruction from earthquake-induced tsunamis in the U.S. and other Pacific Rim countries can result in considerably more damage and deaths than the seismic ground motion. The goal of tsunami research is to save lives and reduce economic losses. To do this, we must develop sufficient scientific knowledge and appropriate engineering tools on which to base comprehensive tsunami mitigation plans and communicate this information effectively to decision makers, the emergency planning community and the public. The overarching theme of this effort is to formulate the complex processes affecting our coastal structures that are driven or affected by turbulent coherent structures (TCS). The role of wall bounded TCS in multiple forcing environments will be examined. Near the seabed, sediment pickup and transport can be significantly enhanced by TCS, leading to extreme scour and infrastructure failure. In the horizontal plane, TCS can appear as giant whirlpools and are commonly associated with extreme damage in ports and harbors. Extensive experiments will be performed at the Oregon State University (OSU), using the Large Wave Flume (LWF) to study the fine detail of TCS significance on nearbed processes, such as mobilization and transport of sediment, as well as the Tsunami Wave Basin (TWB) to characterize the complete hydrodynamic structure of a large, horizontal TCS generated by a port. The observations will be complimented with a wide-reaching numerical effort. To study the detailed TCS generation and its effects on sediment suspension due to transient long wave motion, we will use 3D turbulence resolving simulation models, with grid resolutions on the order of 1 mm. Fully coupled with the flow models will be Discrete Element Models for individual sediment particles, permitting grain-resolving simulation of tsunami-induced transport. Coupling the LWF and the TWB results with the fine resolution numerical tools will allow for predictions of bed mobilization, scour, and harbor wall forces for a generic tsunami problem, including the combined forcing of the mean "uniform" tsunami flow and the very localized, complex velocities due to TCS. The broader impacts of the proposed activities are to ultimately reduce the loss of life and property due to tsunamis through assessing population at risk needs to be aware of the associated risk and be prepared to respond in case of a tsunami warning. Here, we take a two-pronged approach to public education of the hazards possible during a tsunami event. First, a program targeting middle and high school students in coastal states will be closely connected to the experimental research proposed in the TWB. Students will formulate a harbor tsunami response plan, that will be implemented and tested in the TWB. Second, we identify several ways to enhance the transfer of our intellectual efforts to various stakeholders. Our knowledge transfer to engineering practitioners will take the place with 2-3 webinars regarding harbor design, sediment scour, and sediment liquefaction. These webinars will provide information regarding both existing design practices as well as new knowledge gained. The practitioners will be receiving professional development credit and the sessions will be recorded on the NEESHub for future use.