H2020Индивидуална стипендия2018–2021

GraFrontLev · A theoretical, experimental and numerical study of the formation of coarse dry granular fronts and spontaneously self-channelizing levees in debris flows

„Хоризонт 2020“ — Действия „Мария Склодовска-Кюри“

Период: 2018-11-01 → 2021-04-30
Финансиране от ЕС: 183 455 €
Участници: 1
Схема: MSCA-IF-EF-ST

Линиите свързват координатора с партньорите.

Накратко на български

Механизмите за образуване на сухи фронтове от едри скали при кални потоци се анализират чрез модели и експерименти. Разбирането на тези процеси помага за по-добрата оценка на разрушителната сила на природните бедствия и тяхното смекчаване.

Този кратък обзор е генериран от изкуствен интелект

Кратко обяснение, генерирано от езиков модел по текста на CORDIS. Оригиналът е по-долу.

Резултати накратко

A theoretical, experimental and numerical study of the formation of coarse dry granular fronts and spontaneously self-channelizing levees in debris flows

This project looks at (1) the mechanism of the formation of dry granular fronts in debris flows and (2) their feedback on the dynamics of debris flows. The MSCA Research Fellow conducting this research is particularly interested in the development of a depth-averaged model to account for the formation of dry granular fronts and validation of this proposed model by comparing numerical results with experimental measurements. These topics are of interest to fluid dynamicists, civil engineers, geophysicists, and geologists working on the practical mitigation of natural hazards. The formation of large amplitude dry bouldery flow fronts is a spectacular and counterintuitive effect, that is directly responsible for the increased destructive power of debris flows. These poorly understood phenomena are often observed in the field (e.g. Pierson (1986)), large-scale experiments (e.g. Iverson et al. (2010) and Johnson et al.(2012)), and small-scale experiments (e.g. Haas et al. (2015) and Lanzoni et al. (2017)). The traditional geological perspective asserts that the coarse grains are segregated to the top of the flow and they are then preferentially sheared forwards and recirculated by particle-size segregation to develop a dry front. Nevertheless, recent laboratory experiments of mono-disperse flows of grains and water, e.g. Davies (1990) and Taylor (2020), also exhibit such phenomena, which motivated us to explore new formation mechanisms in this project. Formal objectives of this MSCA have been to (1) establish a model by deriving depth-averaged mass and momentum balance equations for the granular and water phases, respectively; (2) perform numerical computations by extending the available numerical code; (3) design an experiment to validate the proposed model; (4) conduct interdisciplinary training through research and skills acquisition; (5) and foster the development of an independent researcher.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз

Цел на проекта

The aim of the GraFrontLev project is to investigate coarse dry granular fronts and self-channelizing levees in debris flows by virtue of a combined study of theory, numerical computation and the experiment. Precisely, the applicant will collaborate with Prof. Gray who is an expert in the field of grain-size segregation of dry granular flows to develop a mathematical model. Analogous to the way in which large grains are segregated to the surface and preferentially transported to flow fronts by velocity shear, the core of this model is to derive a transport equation for the dry layer that forms at the surface of a debris flow, as the granular mixture undergoes shear-induced dilation and the liquid is sucked into the expanded pore space between the grains. This surface dry layer, together with large grains, which also rise to the top of the flow, are then sheared towards the flow forwards to create a highly resistive large rich dry front and shouldered aside to form coarse-grain-enriched levees. These two kinds of contributions can be captured in the proposal by combining a dilatancy law of the granular physics that describes the relation between shear and dilatancy and segregation theory developed by Prof. Gray. To validate the proposed model, numerical simulation will be performed by employing a high-resolution shock-capturing scheme and an experiment will be designed, in which the collected data will be used to inspect the obtained numerical results. It is expected that the research results of this project will have an impact on fluid dynamists, civil engineers and geologist working on debris flows’ prevention by providing them with deep insights into the physics of debris flows and helping to improve predictions of run-out dynamics of debris flows. Additionally, this research is expected to significantly expand the applicant’s knowledge of granular physics under Prof. Gray’s help, and extend the research field of Prof. Gray’s group into multiphase flows.

Оригинален текст от CORDIS (на английски).

Участници

THE UNIVERSITY OF MANCHESTER · ManchesterКоординаторОбединеното кралство