• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >An investigation on the hydrodynamics and sediment dynamics on an intertidal mudflat in Central San Francisco Bay.
【24h】

An investigation on the hydrodynamics and sediment dynamics on an intertidal mudflat in Central San Francisco Bay.

机译：对旧金山湾中部潮间带滩涂水动力和泥沙动力学的研究。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

On an intertidal mudflat in Central San Francisco Bay, we conducted four field experiments between February, 2001 and October, 2003 to investigate hydrodynamic and sediment transport processes. Not only tides and locally driven wind waves bring energy onto the mudflat, but also remotely forced ocean swell and infra-gravity seiching. These energy sources persist and dominate over different time scales, with variation occurring over minutes, hours, and days.; The different hydrodynamic forcing mechanisms superpose upon each other---and interact nonlinearly---in the water column, creating a dynamically varying interaction with the sediment bed. Wind waves produce the largest stresses; however, ocean swell often determines the virtual roughness experienced by the seiche and tidal currents. The boundary layer of the tide is modulated by seiching motions, and is better described by a log-linear profile than a logarithmic profile. However, an analytical log-linear model using acceleration and stratification length scales does not explain the observed velocity structure. Instead, a k-epsilon turbulence closure model (General Ocean Turbulence Model, GOTM) reproduces the unsteady boundary layer structure of the seiching motion. A simple analytical solution (Smith, 1977) suffices to model the boundary layer of ocean swell. Several methods of separating wave energy and turbulence are compared; results show that TKE and dissipation vary with the total energy climate.; Sediment erosion, deposition, and transport also vary on the tidal, seiche, and wave time scales. The tidal component of sediment flux has the largest magnitude, and is often determined by the timing and strength of wind events. Notable fluxes occur at the wave and seiche frequencies. Onshore transport occurs during an ebb tide at the seiche frequency. Sediment concentrations increase when the seiche opposes the ebb current, and decrease when they are aligned. Erosion is not occurring due to a critical stress, but when flow reverses over the rippled bed and causes sediment laden vortices to be ejected. When the seiche opposes the ebb current, waves are more likely to reverse the overall flow and sediment concentration increases. The interactions of multiple frequencies of motion are clearly vital to understanding sediment dynamics on an intertidal mudflat.
机译：在2001年2月至2003年10月之间，在旧金山中央海湾的潮间带滩涂上，我们进行了四个野外实验，以研究水动力和泥沙输送过程。潮汐和局部驱动的风波不仅将能量带到泥滩上，而且还迫使海浪骤增和地心引力下降。这些能源在不同的时间尺度上持续存在并占主导地位，变化持续数分钟，数小时和数天。在水柱中，不同的水动力强迫机制相互叠加-并非线性相互作用-从而与沉积物床产生动态变化的相互作用。风浪产生最大的压力。然而，海浪经常决定着潮汐和潮汐所经历的虚拟粗糙度。潮汐的边界层通过倾斜运动进行调制，与对数剖面相比，用对数线性剖面更好地描述。但是，使用加速度和分层长度标度的解析对数线性模型不能解释观察到的速度结构。取而代之的是，k-ε湍流闭合模型（通用海洋湍流模型，GOTM）再现了俯冲运动的非稳定边界层结构。一个简单的分析解决方案（Smith，1977）足以对海浪的边界层进行建模。比较了分离波能和湍流的几种方法。结果表明，TKE和耗散随总的能源气候而变化。沉积物的侵蚀，沉积和运移在潮汐，潮汐和波浪时间尺度上也不同。泥沙通量的潮汐分量最大，通常取决于风事件的时机和强度。明显的通量出现在波和seiche频率处。陆上运输在退潮期间以seiche频率发生。当seiche对抗退潮时，沉积物浓度增加，而当对齐时，沉积物浓度降低。不会由于临界应力而发生侵蚀，而是当水流在波纹床上倒转并导致充满沉积物的涡流喷出时发生侵蚀。当seiche对抗退潮时，波浪更有可能逆转总体流量，沉积物浓度增加。多个运动频率的相互作用对于理解潮间带滩涂上的沉积物动力学显然至关重要。

著录项

  • 作者

    Talke, Stefan Andreas.;

  • 作者单位

    University of California, Berkeley.;

  • 授予单位 University of California, Berkeley.;
  • 学科 Engineering Environmental.; Physical Oceanography.
  • 学位 Ph.D.
  • 年度 2005
  • 页码 316 p.
  • 总页数 316
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 环境污染及其防治;海洋物理学;
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号