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

小行星9526708 新的模型和计算技术在非线性动力学和改进仪器的实地研究激励重新审查风成沙丘形成的问题。 拟议调查的目标是风成沙丘和沙丘领域的起源和演变的先进模型，制定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在一起。 这项研究的工作计划是逐步进行的，从考虑沙斑（初期沙丘）的成核，继续调查孤立的底形，逐渐处理底形之间的相互作用，并以沙丘领域的整体动态研究结束。 在沙地层面，计算机模拟的跃移沙地加上现场实验的目的是了解为什么和如何成核首先发生和增长。 在底形水平，气流和跃移的计算机模拟发展中的底形，测试和详细的现场测量的约束，将用于探索条件下的沙丘形式与滑动面的演变发生。 在底形-底形相互作用水平上，将进行沙丘侧风流和下风向气流的广泛实地测量，以探讨沙丘对其邻近沙丘的调节作用。 将记录在各种条件下各种人工沙丘之间的相互作用，以制作一份功能图，说明沙丘之间相互作用的结果。 将这些结果与简化的床面力学计算机模拟进行比较。 预计将根据模拟和实地工作中出现的简化假设，得出沙丘区发展的分析模型。 在整个研究过程中，将探讨在任何发展水平和相互作用下可能影响底形的因素，如风速和变率以及供沙量。 由此产生的模型的预测将与自然沙丘场的形态进行比较。

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.