Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 38 for “"Granular flow"”.
-
Multiscale modeling in granular flow
Granular materials are common in everyday experience, but have long-resisted a complete theoretical description. Here, we consider the regime of slow, dense granular flow, for which there is no general model, representing a considerable hurdle to industry, where grains and powders must frequently …
-
Transport-limited aggregation and dense granular flow
… is also discussed. In the second part, dense granular flow inside silos and hoppers is investigated using high-speed imaging and the results are compared to existing theories. While mean velocity fields are in qualitative agreement, the diffusion and mixing of particles are contradictory to …
-
A framework for continuum simulation of granular flow
Granular materials have eluded continuum modeling attempts for centuries. A significant chunk of the complexity lies in the trans-phase behavior of granular media; while the material has a yield stress and can therefore act as a solid body, grains may also flow quickly much like a liquid. At low …
-
Stochastic and deterministic models for dense granular flow
Granular materials such as sand or gravel surround us everyday and yet remain poorly understood. In this thesis, two models are developed for dense granular flow, each capable of predicting flows with accuracy in multiple environments. The models are based on differing perspectives of grain-level …
-
A granular flow model of an annular shear cell
… minerals to be extracted are best modelled using granular flows. A single rheological description that captures all the features of granular flows has not yet been realised, although considerable progress towards a complete theory has been made. Existing models of such horizontally stirred mills …
-
Dense granular flow in rotating drums: a computational investigation of constitutive equations
The constitutive laws of dense granular flow are investigated. Simulations of a drum, with periodic boundary conditions, rotating at varying speeds are performed. From the resulting data, kinematic and kinetic fields are extracted and used to investigate the validity of constitutive relations …
-
Granular flow modelling of rotating drum flows using positron emission particle tracking
Tumbling mills are characterized by a flowing granular mixture comprising slurry, ore and grinding media. Akin to fluid flow, a rheological description underpinning granular flow has long been expected and pursued by many researchers. Unfortunately, no single theory has hitherto been able to …
-
A nonlocal dense granular flow model implemented in the material point method
A nonlocal model for dense granular flow is implemented in the material point method (MPM), an extension of the finite element method (FEM) for solid mechanics. The nonlocal model used has shown great predictive capability for dense flows when implemented in the finite element framework, but …
-
Discrete element simulations and constitutive modeling of dense granular flows
… and explore the rheology of</p> <p>dense granular flow, in particular the phenomenon of regime</p> <p>transition, using both microscale DEM (discrete element method)</p> <p>simulations and macroscale modeling methods. The rheology of dense sheared granular flow in a Couette device is …
-
Computer simulations for a scholastic theory of granular drainage
There is a surprising lack of good models for granular flow. In 2002, Bazant proposed a new stochastic kinematic model of granular drainage from a silo. The new model rests on the notion that flow in the silo is caused by the migration of extended regions of excess interstitial space upward from …
-
Order and Asymmetry in Jammed Systems
<p>Granular matter is composed of particles that are big enough that thermal effects may be neglected. We studied both granular flow and granular statics using numerical simulation. In granular flow, we simulated 2D granular flow in a hopper. A hopper is a container with an opening at the bottom. …
-
Multi-scale multiphase modelling of granular flows
Geophysical hazards usually involve multiphase flow of dense granular solids and water. Understanding the mechanics of granular flow is of particular importance in predicting the run-out behaviour of debris flows. The dynamics of a homogeneous granular flow involve three distinct scales: the …
-
Shared memory parallelization for large scale 3D polyhedral particle simulations
Granular materials such as sands, gravels, railroad ballast, and rock are inherently highly heterogeneous and anisotropic. While they are known as one of the most widely used materials in industry, their complex behaviors remain not fully understood. Particle-based numerical methods were introduced …
-
Developing a mechanistic model for flow through a perforated plate with application to screening of particulate materials
… based understanding of the behaviour of the granular system. To go beyond the current state-of-the-art in screen modelling requires a clear understanding of the particle motion along a dynamic (vibrating) inclined plane. Central to this understanding is the notion that granular systems …
-
Numerical Simulation of Liquid-Solid Circulating Fluidized Beds
… to simulate the hydrodynamics of the two phase flow in an LSCFB riser. The model is based on Eulerian–Eulerian (E-E) approach incorporating the kinetic theory of granular flow. The predicted flow characteristics agree well with our earlier experimental data. Furthermore, the model can predict …
-
Inference and Entropy in Free-Surface Flows
In spite of the ubiquity of free-surface flows across both nature and industry, theoretical and numerical modelling remains challenging. Continuum flows, whether Newtonian or Non-Newtonian, are governed by the Navier–Stokes equations, whilst the particle-particle interactions within a granular flow …
-
Rotary kiln transport phenomena: a study of the bed motion and heat transfer
… distribution of this thermal energy within the granular bed. Although the former has been reasonably well characterized, the latter has not, mainly because of difficulty in predicting flow within the bed. Bed motion in the cross-section is fundamental in determining advective heat transport as …
-
Discrete Element Modeling of Granular Flows in Vibrationally-fluidized Beds
… project was to develop a model for the motion of granular media under vibration in a tub vibrator. For such a system, it was decided that a discrete element method (DEM) was the most appropriate tool to model bulk velocity and circulation of media. In the first phase of the work, a vibratory …
-
Reduced-order modeling of granular intrusions driven by continuum approaches
Granular intrusions such as ballistic impacts, vehicular and animal locomotion in natural terrains, and stirring of materials in industrial processes are common. Granular media often exhibits coupled solid-like and fluid-like multiphase characteristics in such systems that are commonly not shown by …
-
Energy propagation in jammed granular matter
The systems built from dense granular materials are very important due to their relevance to a number of technological and other fields. However, they are difficult to study in particular due to a lack of accurate continuum description. In this work, studies on these systems are presented using …
Page 1 of 2