Support for US Participants and Phrasing Open Questions in the Kavli Program on Fluid-Particle Transport

1332328PI：Jenkins一个为期三个月的项目将于2013年9月23日至12月20日在加利福尼亚州圣巴巴拉的卡夫利理论物理研究所举行，该项目致力于地球物理流中流体中介的粒子传输。该计划将提供一个机会，就必须解决的重要问题和需要回答的关键问题达成共识，以促进对自然流体-颗粒流动的理解。与该计划相关的是两个焦点周和一个总结会议。人们对自然流体-颗粒流动的许多要素知之甚少。例如，在一定的颗粒浓度和颗粒-流体质量密度比范围内的湍流中，非定常平均速度和脉动速度对颗粒的影响；颗粒之间以及颗粒床表面的颗粒与流体之间相互作用的性质；以及在水和风驱动的系统中床上大尺度特征形成的机制。在为期三个月的计划中，将举行两个焦点周和一个总结会议，研究人员将不参加该计划。一个焦点周将专注于颗粒与流体浑浊的相互作用，另一个焦点周将集中在床层的侵蚀和沉积机制上。结束语《自然界中的颗粒流》将在项目的最后一周进行，试图提供对其主题的理解状态的概述。颗粒流发生在自然和许多工业过程中。人们对它们的理解不如只涉及一种流体的流动那样好。这是因为流体与颗粒之间以及流体中颗粒之间的相互作用是复杂的，不容易用数学来描述。重要的是要尝试实现这样的描述，以便预测诸如风沙形成沙丘、威胁管道和通信电缆的水下雪崩、粉尘和颗粒雪的雪崩以及火山喷发期间火山灰和热气或岩石在熔岩中的流动等现象。

1332328PI: JenkinsA three-month long program devoted to fluid-mediated particle transport in geophysical flows will take place at the Kavli Institute for Theoretical Physics in Santa Barbara, California, between September 23 and December 20, 2013. This program will provide an opportunity to develop a consensus regarding the important issues that must be addressed and the key questions to be answered in order to advance the understanding of natural fluid-particle flows. Associated with the program are two focus weeks and a concluding conference. There are many elements of natural fluid-particle flows that are poorly understood. Examples are the in-fluence of the unsteady mean and fluctuating velocities on particles in a turbulent flow over a range of particle concentration and ratios of particle-fluid mass density; the nature of the inter-actions between particles and between the particles and fluid at the surface of a particle bed; and the mechanisms by which large-scale features develop on the bed in systems driven by water and the wind. Within the three-month program, two focus weeks and a concluding conference will take place that will involve researchers not attending the program. One focus week will be devoted to the interactions of particles with fluid turblence, the other will concentrate on mechanisms of erosion and deposition at the bed. The concluding confence, "Particle-Laden Flows in Nature", will take place during the last week of the program and attempt to provide an overview of the state of understanding of its subject.Particle-laden flows occur naturally and in many industrial processes. They are not so well understood as flows involving only a fluid. This is because the interaction between the fluid and the particles and those between particles in the fluid are complicated and not easy to describe mathematically. It is important to try to achieve such descriptions in order to predict phenomena such as dune formation by wind-blown sand, underwater avalanches that threaten pipeline and communications cables, avalanches of powder and granular snow, and flows of ash and hot gases or rocks in molten lava during volcanic eruptions.