کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6427051 1634476 2013 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Rigid obstacle impacted by a supercritical cohesive granular flow using a 3D discrete element model
ترجمه فارسی عنوان
مانع سفت و سخت توسط جریان گرانشی یکپارچه فوق بحرانی با استفاده از یک مدل عنصر دیجیتالی گسسته
کلمات کلیدی
جریان گرانشی انعطاف پذیر، تعامل جریان / مانع، ضریب کشیدن، تماس با شبکه، مدل عنصر گسسته، باتلاقهای مرطوب و برف،
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات علوم زمین و سیاره ای (عمومی)
چکیده انگلیسی

This study examines the drag coefficient of an obstacle impacted by a 3D cohesive granular flow using a discrete element model. A specific numerical setup is used to carry out reproducible and controlled normal impact simulations, in which the upstream flow properties are fully controlled parameters. The micromechanical contact model involves the physical properties of friction, normal elastic-plastic repulsion, dissipation, and a normal cohesion factor that induces bulk cohesion in the granular assembly. The effect of cohesion on the obstacle load is investigated through a micro-scale analysis. We show that increasing the cohesion leads to an increase of the obstacle drag, through a densification of the contact network, which enhances the transmission of contact forces to the obstacle. This experiment is extended to a wide range of supercritical flows, with Froude numbers between 1.5 and 11.2. The resulting drag coefficient curves are represented as power law functions of the Froude number. We then demonstrate the dependency of the power law exponent on the ratio between inertia and gravitational forces. Our results suggest that the assessment of drag coefficient critical values by conventional avalanche protection guidelines could be improved by a mechanical consideration of cohesion for certain snow types.

► Supercritical cohesive granular flows impacting a normal obstacle are simulated. ► A microscopic cohesion is introduced to create cohesion at the macroscopic scale. ► The effect of cohesion and the Froude number on the drag coefficient is investigated. ► Increasing cohesion densifies the contact network and increases the drag coefficient. ► The drag coefficient is plotted as a function of the Froude number between 1.5 and 11.2.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Cold Regions Science and Technology - Volume 85, January 2013, Pages 232-241
نویسندگان
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