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: 9526708
• 负责人: Gary Kocurek
• 金额: $ 17.27万
• 依托单位: University of Texas at Austin
• 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 2000-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9526708&HistoricalAwards=false
• 关键词: Collaborative; Research; Micromechanics; Eolian; Sand

Kocurek 9526708 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 an d 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.

非线性动力学的新模型和计算技术以及野外研究仪器的改进促使人们重新审视风成沙丘的形成问题。提出的研究目标是建立风成沙丘和沙丘场的起源和演化的先进模型，计算出这些模型的预测结果，并对它们进行严格的实地测试。这项研究将采用综合方法，将计算机模拟、实地观察和实验以及分析模型结合起来。这项研究的工作计划以循序渐进的方式进行，从考虑沙块（初期沙丘）成核开始，继续调查孤立的河床，逐步处理河床之间的相互作用，最后研究沙丘场的总体动力学。在沙粒水平上，计算机模拟沙粒上的跃变，再加上实地实验，目的是了解为什么和如何先成核，然后生长。在河床层面，通过详细的实地测量测试和约束，对正在形成的河床上的气流和跳跃进行计算机模拟，将用于探索在何种条件下演变成带有滑面的沙丘形态。在坡面-坡面相互作用水平上，将对沙丘的横向和下风气流进行广泛的野外测量，以探索沙丘对其相邻沙丘的调节作用。在一系列条件下，各种沙丘之间的相互作用将被记录下来，以产生描述沙丘-沙丘相互作用结果的功能图。这些结果将与简化的床型力学的计算机模拟进行比较。预期将根据从模拟和实地工作中得到的简化假设，得出一个沙丘场发展的分析模型。在整个研究过程中，将探索在任何发展和相互作用水平上可能影响地形的因素，如风速和变异性以及沙子供应。所得模型的预测结果将与自然沙丘场的形态进行比较。