Frictional fluid dynamics of granular flows; uniting experiments, simulation and theory

流体驱动的颗粒过程在整个工业和自然世界中是司空见惯的。全球能源消费的很大一部分与建筑、农业、制药业以及食品和能源部门的谷物和颗粒物加工有关。与此同时，河流和冰川下的侵蚀，以及滑坡和天坑形成等自然灾害，都因气候变化造成的降水模式变化和陆地冰融化而加剧。在我们努力实现净零排放的过程中，我们必须全面了解颗粒流的物理特性，这既可以减少我们的碳足迹，也可以更好地管理地球物理环境的快速变化。流体驱动的颗粒流仍然知之甚少。流体对颗粒的影响、颗粒材料之间的摩擦以及颗粒本身的性质都导致了高度复杂的行为。FFDflow奖学金将进行广泛的实验室实验，以观察各种条件下的流体驱动流，以揭示其潜在的物理学，同时考虑到所有这些方面。这些流动也将使用理论模型和计算机模拟进行探索，这是一项合作基准研究的一部分，以验证用于流体驱动颗粒流的各种模型。FFDflow奖学金还将研究如何在冰川下的冰碛物中发生流体驱动的流动。这是一个特别紧迫的问题，因为海洋终止冰流（快速流动冰的走廊）的加速是海平面上升的巨大不确定性的来源，冰流的动态在很大程度上受到冰和床之间的界面及其周围发生的过程的控制。将使用旨在探索冰川下环境的实验室装置进行一系列实验，目的是更好地了解在这些环境中颗粒流动的方式以及它如何影响上面的冰。

Fluid-driven granular processes are commonplace throughout the industrial and natural worlds. A large share of global energy consumption relates to the processing of grains and particulate matter in construction, agriculture, the pharmaceutical industry, and the food and energy sectors. Meanwhile, erosion in rivers and underneath glaciers, as well as natural hazards such as landslip and sinkhole formation, are exacerbated by changing precipitation patterns and the melting of land ice caused by climate change. As we strive to achieve net zero, it is vital that we develop a comprehensive understanding of the physics of granular flow, both to reduce our carbon footprint and to better manage rapid changes in our geophysical environment.Grain flows driven by fluid remain poorly understood. The fluid's influence on the grains, the friction between the granular material, and the properties of the grains themselves all result in highly complex behaviour. The FFDflow fellowship will carry out extensive laboratory experiments to observe fluid-driven flows across a wide range of conditions to reveal their underlying physics, taking into consideration all of these aspects. These flows will also be explored using theoretical models and computer simulation forming part of a collaborative benchmark study to validate a variety of models for use in fluid-driven granular flows.The FFDflow fellowship will also study how fluid-driven flows can occur in the till underneath glaciers. This is a particularly pressing matter as the acceleration of marine-terminating ice streams (corridors of fast flowing ice) is a source of huge uncertainty regarding sea-level rise, and the dynamics of ice streams is largely controlled by processes occurring at and around the interface between ice and the bed. A series of experiments will be performed using a laboratory setup designed to explore the environment underneath a glacier, with the aim of obtaining a better understanding of the way in which grain flow arises in these settings and how it might impact the ice above.