Workshop on inertial particles in turbulence: theory and applications from engineering to geophysics

众所周知，即使在均匀湍流中，由于均匀湍流的小尺度变化和惯性粒子对这些变化的有限响应时间，惯性粒子也可以形成团簇或不均匀性。这产生了丰富多样的模式，几十年来一直是许多研究的主题。这个问题在许多方面都有表现，如化学工程和核能工业所关注的流化床、河流中的沉积、发动机中的喷雾液滴、制药工业中粉末的产生以及云的形成。尽管经过多年的研究，人们对惯性粒子的性质有了很深的了解，但仍然存在一些突出的问题。这些包括加速度的作用，碰撞的影响以及粒子统计如何随斯托克斯数变化，斯托克斯数是表征惯性粒子跟随湍流的无量纲数。在各种工业、环境和地球物理的情况下，重力、离心力、科里奥利力甚至电磁力等力可能变得很重要，并可能改变粒子统计随斯托克斯数的变化。在工程和地球物理情况下的另一个问题是这些不均匀性对液滴蒸发和热传递（包括辐射加热）的影响。本次研讨会的目的是将那些在工程和物理情况下研究湍流中惯性粒子的人聚集在一起，以评估当前的知识水平，规划未来的研究和促进合作。正是通过这些不同但重叠的学科的相互作用，我们希望对上述问题产生一些答案。

It is well known that even in a homogeneous turbulent flow, inertial particlescan form clusters, or inhomogeneities, on account of the small-scale variationof the homogeneous turbulent fluid and the finiteresponse time of the inertial particles to these changes.This generates a rich variety of patterns that have been the subjectof much research over several decades. There aremany contexts in which this problem manifests itself, in fluidised bedswhich are of interest to the chemical engineering and nuclearpower industries, in sedimentation in rivers, in spray droplets in engines,in the creation of powders in the pharmaceutical industryand in the formation of clouds. There is thus considerable expertiseon this issue across a wide range of disciplines.Despite a wealth of understanding on inertial particles in turbulencedeveloped over many years of research, there remain several outstandingproblems. These include the role of acceleration, the effect of collisionsand how the particle statistics vary with the Stokes number, the dimensionlessnumber which characterises how closely the inertial particlesfollow the turbulent fluid. In various industrial, environmental andgeophysical situations forces such as gravity, centrifugaland Coriolis forces and even electromagnetic forces canbecome important and may change the variation of the particlestatistics with the Stokes number. A further issue in both engineeringand geophysical situations is the impact of these inhomogeneities onevaporation of droplets and heat transfer including radiative heating.The aim of this workshop is to bring together those working oninertial particles in turbulence in both engineering and geophysicalsituations to assess the current state of knowledge,plan future research and foster collaboration.It is through the interaction of these diverse but overlapping disciplines thatwe hope to produce some answers to the questions posed above.