Transient wave-induced instability in shallow water bottom boundary layers

2004年的苏门答腊-安达曼地震和印度洋海啸是人类近代史上最具破坏性的自然灾害之一。灾难发生后，科学家和工程师一直在共同努力，在印度洋地区建立早期海啸预警系统和减轻海啸危害的项目。提高我们对海啸认识的一个很有希望的方法是利用海啸产生的沉积物。我们的长期研究目标是将海啸水动力学与大陆架和海岸带沉积物的输运过程联系起来。pi认为，达到这一目标的途径是了解孤立波（或前缘洼地）下的边界层流动特性。最近对表面波和内波的研究表明，在一定雷诺数下，流动减速阶段可能发生全局不稳定（一种特定类型的固定空间范围的自发触发剪切不稳定），导致旋涡脱落和湍流。PI计划在此扩展Co-PI开发的谱多域惩罚方法模型，以进一步研究二维和三维孤立波（和LDN）下的边界层流动。这里概述的研究活动是在几个科学和工程领域之间的界面-海洋学，流体力学和海岸工程，并将作为它们之间的桥梁。这项计划中的研究是一项长期基础研究计划的第一阶段，旨在将海啸流体动力学与海啸留下的沉积物联系起来。除了在同行评议的文献中发表外，还将通过发展和维持一个项目网站来加速项目期间的传播。该项目将培养1名博士研究生，接受数值方法、数据分析和解析解技术方面的前沿培训。他/她还将接受扎实的实验方法培训，以便他/她能够进行模型/数据比较。此外，学生将接受报告写作和口头陈述的培训，并鼓励他/她参加技术会议和会议。

CBET-0756327LiuThe 2004 Sumatra-Andaman earthquake and Indian Ocean tsunami is one of most devastating natural disasters in recent human history. After the disaster, scientists and engineers have been working together to establish an early tsunami warning system and tsunami hazard mitigation programs in the Indian Ocean region. A promising approach for improving our understanding of tsunamis is to use the deposits they create. The long term goal of our research is to relate tsunami hydrodynamics to sediment transport processes on continental shelf and coastal zone. The PIs believe that the path to reach this goal is to understand the boundary layer flow characteristics under solitary (or leading depression) waves. Recent studies on surface and internal waves show that global instabilities (a particular type of spontaneously triggered shear instability of fixed spatial extent) could occur during the flow deceleration phase at certain Reynolds numbers, leading to vortex shedding and turbulence. The PI's plan here to extend the spectral multidomain penalty method model developed by the Co-PI to further investigate the boundary layer flows under solitary (and LDN) waves in both 2D and 3D. The research activities outlined here are at the interface between several field of science and engineering- oceanography, fluid mechanics, and coastal engineering and will serve as a bridge among them. The planned research is the first phase of a long term fundamental research program, which aims at correlating the tsunami hydrodynamics with the sediment deposits left behind by the tsunamis. Dissemination during the project will be expedited by developing and maintaining a project web site, in addition to publishing in the peer-reviewed literature. The project will train one PhD student who will receive cutting-edge training in numerical methods, data analysis and analytical solution techniques. He/she will also have a solid training in experimental methods so that he/she will be capable of performing model/data comparisons. Furthermore, the student will be trained in report writing and oral presentation and he/she will be encouraged to attend technical conferences and meetings.