Support for U. S. Participants in the Max Planck Program on Geophysical Particle-Fluid Flows (Dresden, Germany, March 14-April 15, 2016)

提案编号：1619768该提案寻求资金，以部分支持约25名美国科学家参加为期五周的项目（包括注册和旅行），该项目将于2016年3月14日至4月15日在德国德累斯顿的马克斯普朗克复杂系统物理研究所进行，该项目致力于对涉及粒子和流体的地球物理流动进行两阶段建模。本次研讨会的动机是需要了解自然的流体-颗粒流动现象，例如(a)在一定的颗粒浓度和颗粒-流体质量密度比范围内，湍流中非定常平均速度和波动速度对颗粒的影响；(b)颗粒之间以及颗粒床表面颗粒与流体之间相互作用的性质；(c)在由水或风驱动的系统中，大型特征在河床上形成的机制。地球物理流发生在长度尺度、时间尺度和浓度的范围内，这对目前基于Navier-Stokes方程的计算方案提出了问题。目前，两相连续体公式最有希望描述这种流动，但它们需要正确的物理模型来描述流体和颗粒之间的相互作用。这些模型的开发将是本次研讨会的重点。了解研讨会所关注的自然流动，将有助于对对人类生活和经济非常重要的现象进行建模和预测，例如沙尘暴、山腰上的岩石和积雪融化、粉末和颗粒状雪的雪崩、海岸线、河流和溪流以及大陆架上的波浪沉积物的运输。即使是会导致航空运输和农业中断的火山气体和火山灰的羽流和涌流也属于这一类。

PI: Jenkins, James T. Proposal Number: 1619768 The proposal seeks funds to partially support the attendance (which includes the registration and travel) of about 25 US scientists to the five-week long program devoted to two-phase modeling of geophysical flows that involve particles and fluids that will take place at the Max Planck Institute for the Physics of Complex Systems in Dresden, Germany, between March 14th and April 15th, 2016.This symposium is motivated by the need to understand natural fluid-particle flow phenomena, such as (a) the influence 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; (b) the nature of the inter-actions between particles and between the particles and fluid at the surface of a particle bed; and (c) the mechanisms by which large-scale features develop on the bed in systems driven by water or wind. Geophysical flows occur over a range of length scales, time scales, and concentrations that pose problems for present computational schemes based on the Navier-Stokes equations. At the present time, two-phase continuum formulations are the best hope for describing such flows, but they require correct physical models for terms that describe the interactions between the fluid and the particles. The development of such models will be the focus of this workshop.Understanding the natural flows upon which the workshop is focused would benefit modeling and prediction of phenomena quite important for human life and for the economy, such as sand storms, torrents of rock and snow-melt down mountainsides, avalanches of powder and granular snow, transport of sediment by waves at coastlines, in rivers and streams, and down continental shelves. Even plumes and surges of volcanic gas and ash that can cause disruption in air transportation and agriculture fall into this category.