Waves in fluids and solids

扰动和数值技术相结合，将被用来调查各种波的传播问题的实际利益。这些变化包括海洋沉积物的液化、高压声波振荡和沿海含水层的流动。液化会引起海洋结构物的破坏，如海床失去支撑力，引起稳定性问题。目的之一是探索渐进液化的机制，通过开发模型，为不同的土壤情况。了解桑迪地下水动力学对于侵蚀和盐水入侵是很重要的。建议考虑土壤分层对地下水位波动的影响。从湖底和尾矿池底部的流体泥层中重新悬浮物质可能具有实际重要性。一种机制是由于表面波运动在流体泥浆和上覆水之间的界面处产生波。需要检查的主题是在非线性和粘性制度的相互作用，以及由于波浪破碎的质量扩散。当水从分层水库中抽出时，低流量的水流被限制在靠近水槽的狭窄层内。这一现象被称为选择性取水，被用作一种管理技术，以供应具有所需质量的水。地形特征，如收缩或岩床影响流出质量。目标是量化形貌对撤回层的厚度和密度的影响。最近人们对在特殊形状的容器中产生高压无冲击气体振荡很感兴趣。在没有冲击的情况下，对于相同的能量输入，会产生更高的压力。在解释这种现象时，挑战在于理解几何与非线性的相互作用。目的是将这些概念扩展到球形几何问题，例如考虑球壳中非均匀气体的振荡。

A combination of perturbation and numerical techniques will be used to investigate a variety of wave propagation problems of practical interest. These range from liquefaction in marine sediments, to high-pressure acoustic oscillations, and flows in coastal aquifers. Liquefaction can cause the failure of marine structures, such as the loss of supporting power of the seabed, causing stability problems. One objective is to explore the mechanism of progressive liquefaction by developing models for different soil situations. Knowledge of groundwater dynamics in sandy beaches is important for erosion and saltwater intrusion. It is proposed to consider the effects of soil stratification on water table fluctuations. Re-suspension of material from the layers of fluid mud at the bottom of lakes and mine-tailings ponds can be of practical importance. One mechanism is the generation of waves at the interface between the fluid mud and the overlying water due to surface wave motion. Topics that need examination are the interaction in the nonlinear and viscous regimes, and mass diffusion due to wave breaking. When water is withdrawn from a stratified reservoir, the flow at low discharges is confined to a narrow layer adjacent to the sink. This phenomenon, known as selective withdrawal, is used as a management technique for the supply of water with desired qualities. Topographic features such as a contraction or a sill affect the outflow quality. A goal is to quantify the effects of topography on the thickness and density of the withdrawal layer. There has been interest recently in producing high-pressure shockless oscillations of gasses in specially shaped containers. With no shocks, higher pressures result for the same energy input. In explaining this phenomenon, the challenge is to understand the interaction of the geometry with the nonlinearity. The intent is to extend these concepts to problems with spherical geometry, for example considering oscillations of an inhomogeneous gas in a spherical shell.