Collaborative Research: Micromechanics of Eolian Sand Dune Development: Computer Simulations and Field Experiments

合作研究：风成沙丘发育的微观力学：计算机模拟和现场实验

• 批准号: 9526439
• 负责人: Brad Werner
• 金额: $ 19.91万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-03-01 至 1999-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9526439&HistoricalAwards=false
• 关键词: Collaborative; Research; Micromechanics; Eolian; Sand

Werner 9526439 New models and computational techniques in nonlinear dynamics and improved instrumentation for field studies motivate a re-examination of the problem of eolian dune formation. The goals of the proposed investigation are to be advance models for the origin and evolution of eolian dunes and dune fields, to work out the predicted consequences of these models, and to subject them to rigorous field testing. The study will follow an integrated approach, bringing together computer simulation, field observation and experimentation, and analytical models. The work plan for the study proceeds in step-wise fashion from consideration of sand patch (incipient dune) nucleation, continuing with investigation of isolated bedforms, graduating to treatment of interactions between bedforms, and ending with study of the overall dynamics of dune fields. At the sand-patch level, computer simulations of saltation over sand patches plus field experimentation are aimed at understanding why and how nucleation first occurs and growth follows. At the bedform level, computer simulation of airflow and saltation over developing bedforms, tested and constrained by detailed field measurements, will be used to explore the conditions under which evolution to dune forms with slipfaces occurs. At the bedform-bedform interaction level, extensive field measurements of airflow lateral and downwind from dunes will be performed to probe the regulating effects of dunes on their neighbors. The interactions between a variety of constructed dunes under a range of conditions will be documented to produce a functional map describing the results of dune-dune interactions. These results will be compared to simplified computer simulations of bedform mechanics. It is expected that an analytical model of dune field development, based on simplifying assumptions emerging from the simulation nd field efforts, will result. Throughout the entire study, factors that may affect bedforms at any of the levels of development and interaction, such as wind velocity and variability and sand supply, will be explored. Predictions of the resulting model will be compared with the morphology of natural dune fields.

Werner 9526439非线性动力学中的新模型和计算技术和改进的现场研究仪器促使对Eolian Dune形成问题的重新检查。 拟议的调查的目标是成为Eolian Dunes和Dune领域起源和演变的预先模型，以确定这些模型的预测后果，并使它们进行严格的现场测试。 该研究将遵循一种综合方法，将计算机模拟，现场观察和实验以及分析模型汇总在一起。 该研究的工作计划以逐步的方式从考虑砂斑（初期沙丘）成核的考虑，继续研究孤立的床形，毕业于床形之间的相互作用，并以研究沙丘领域的整体动态结束。 在沙子点水平上，盐斑块上盐的计算机模拟以及田间实验旨在了解成核首次发生和如何发生和生长。 在床形级别，将使用详细的现场测量测试和约束的床形上对气流和盐分的计算机模拟，以探索发生带有滑移的沙丘形式的条件。 在Bedform-perform的相互作用水平上，将进行气流横向和沙丘下风的广泛田间测量，以探测沙丘对邻居的调节作用。 将记录各种条件下各种构造的沙丘之间的相互作用，以产生描述Dune-Dune相互作用结果的功能图。 这些结果将与简化的床形力学的计算机模拟进行比较。 可以预期，基于简化的模拟现场工作中出现的假设的分析模型将产生。 在整个研究中，将探索可能影响任何开发和相互作用水平的床形的因素，例如风速，可变性以及沙子供应。 将结果模型的预测与天然沙丘场的形态进行比较。