Research Interests:
Purpose–The purpose of this paper is to show how simulation of the flow of particulates and fluids using discrete element modelling (DEM) and smoothed particle dynamics (SPH) particle methods, offer opportunities for better understanding... more
Purpose–The purpose of this paper is to show how simulation of the flow of particulates and fluids using discrete element modelling (DEM) and smoothed particle dynamics (SPH) particle methods, offer opportunities for better understanding the dynamics of flow processes. Design/methodology/approach–DEM and SPH methods are demonstrated in a broad range of computationally-demanding applications including comminution, biomedical, geophysical extreme flow events (risk/disaster modelling), eating of food by humans and ...
Research Interests:
Improvement of swimming performance involves changes to technique, endurance and strength, but the relationship between these factors cannot be predicted precisely for an individual athlete. Recent advances in computational models of... more
Improvement of swimming performance involves changes to technique, endurance and strength, but the relationship between these factors cannot be predicted precisely for an individual athlete. Recent advances in computational models of swimming provide the opportunity to study these relationships in a virtual environment. Unlike in physical experimentation, the forces on individual body segments, torque about body joints and joint powers can be calculated in the model. These model outputs allow new insight into the loading on the body from the fluid along with the internal biomechanical forces that result. We use a coupled Biomechanical-Smoothed Particle Hydrodynamics (B-SPH) model to calculate joint torque and joint powers for the arms of a male elite athlete performing a freestyle stroke. Results show the large demand on the muscles of the arm, especially those spanning the shoulder. Future developments and applications of the model are discussed.
ABSTRACT Kayak racing performance is known to be dependent on both technique and strength, but the relationship between these attributes and performance is not well understood. Complete experimental measures of stroke technique and the... more
ABSTRACT Kayak racing performance is known to be dependent on both technique and strength, but the relationship between these attributes and performance is not well understood. Complete experimental measures of stroke technique and the interactions between the water and the paddle and the boat are not practical in the racing environment. Instead, simulation using computational fluid dynamics may be used to study this system.
ABSTRACT Impact with the water during a 10 m platform dive imparts large forces onto the diving athlete. Wrist and back injuries are common and are thought to be related to cumulative damage from many overload events, rather than one... more
ABSTRACT Impact with the water during a 10 m platform dive imparts large forces onto the diving athlete. Wrist and back injuries are common and are thought to be related to cumulative damage from many overload events, rather than one acute high loading event. Experimental measures of forces on the body are impractical and instead computational simulation is appropriate to estimate this loading.
Research Interests:
ABSTRACT We investigate the fall of planar granular columns in a quasi-static regime using a combination of laboratory experiments and DEM modelling. Columns made of alternatively coloured sand layers are initially laid out in a box and... more
ABSTRACT We investigate the fall of planar granular columns in a quasi-static regime using a combination of laboratory experiments and DEM modelling. Columns made of alternatively coloured sand layers are initially laid out in a box and then released when a retaining wall is set in slow motion with constant speed. The two-dimensional flow involves failure of the granular material along multiple slip planes at different stages of the deformation leading to complex folding patterns. 2D DEM simulation is able to qualitatively reproduce a range of essential elements of this flow with particle shape being an important contributor to the mobilisation of specific slip planes.
Research Interests:
Several new families of low-resonance periodic orbits have been found for the slowly rotating triaxial Schwarzschild potential. Their bifurcation structure is complicated and involves a number of equatorial plane instability strips and... more
Several new families of low-resonance periodic orbits have been found for the slowly rotating triaxial Schwarzschild potential. Their bifurcation structure is complicated and involves a number of equatorial plane instability strips and three-dimensional cascade structures. Their orbital behavior and stability are also examined.
Research Interests:
Page 1. Progress in Computational Fluid Dynamics, Vol. 10, Nos. 5/6, 2010 327 Copyright © 2010 Inderscience Enterprises Ltd. Screw conveyor performance: comparison of discrete element modelling with laboratory experiments Philip J. Owen*... more
Page 1. Progress in Computational Fluid Dynamics, Vol. 10, Nos. 5/6, 2010 327 Copyright © 2010 Inderscience Enterprises Ltd. Screw conveyor performance: comparison of discrete element modelling with laboratory experiments Philip J. Owen* and Paul W. Cleary ...
Research Interests:
Research Interests: Mechanical Engineering, Civil Engineering, Discrete Element Method, Finite Element Analysis, Efficient Algorithm for ECG Coding, and 8 moreSearch Algorithm, Design Methodology, Granular Material, Three Dimensional, Interdisciplinary Engineering, Engineering Computations, Concrete and Hot Mix Asphalt, and HOTMIX ASPHALT CONCRETE MIX
ABSTRACT Understanding how the permeability of a porous medium changes as function of solid fraction and pore geometry is vital in many significant areas. Here, we construct a number of different porous media via computer methods. We then... more
ABSTRACT Understanding how the permeability of a porous medium changes as function of solid fraction and pore geometry is vital in many significant areas. Here, we construct a number of different porous media via computer methods. We then simulate the flow of a viscous liquid through the solid packing using the Smoothed Particle Hydrodynamics (SPH) and Lattice Boltzmann (LB) methods. Qualitative comparisons of flow between the two methods are generally good as are the quantitative permeability comparisons. The relative computational efficiency of both methods is examined with the LB method being superior to SPH for this application.
Research Interests:
ABSTRACT Most DEM analyses of ball and stirred mills reported to date have considered only media motion and its interaction with the mill lifter configuration. For SAG mills, a large fraction of the feed material can already be well... more
ABSTRACT Most DEM analyses of ball and stirred mills reported to date have considered only media motion and its interaction with the mill lifter configuration. For SAG mills, a large fraction of the feed material can already be well represented in DEM models. But for other mill types with much finer feed, the number of feed particles has been prohibitive to include them directly in the calculations. The C-MIS code is now sufficiently powerful to allow inclusion of ore particles within a short periodic section of a small pilot (or large lab) scale mill. This provides the opportunity to better understand the effect of media on the interstitial bed of powder and of the powder on the media. In this paper, the complete pilot mill was first simulated with media only included. A truncated size distribution was then used to represent ore particles in a periodic simulation of about one tenth of the mill length. The results allowed for analysis of the effect of rock on the overall flow, and the influence of the fl ow and collisional environment on the fine ore particles. The normal, shear and total energy consumptions were also analysed for different powder fi ll levels.
Research Interests:
... simulations. Delaney, Gary W., Cleary, Paul W., Sinnott, Matt D. and Morrison, Rob D. (2010). ... Statistics. Created: Thu, 09 Dec 2010, 13:39:12 EST by Karen Holtham on behalf of Julius Kruttschnitt Mineral Research Centre - Detailed... more
... simulations. Delaney, Gary W., Cleary, Paul W., Sinnott, Matt D. and Morrison, Rob D. (2010). ... Statistics. Created: Thu, 09 Dec 2010, 13:39:12 EST by Karen Holtham on behalf of Julius Kruttschnitt Mineral Research Centre - Detailed History. ...
Research Interests:
... This ensures that the density variation is less than 1% and the flow can be regarded asincompressible. ... Improvements to both product quality and process productivity can be brought about through improved die design. ... (1999)... more
... This ensures that the density variation is less than 1% and the flow can be regarded asincompressible. ... Improvements to both product quality and process productivity can be brought about through improved die design. ... (1999) compared isothermal SPH simulations with water ...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
ABSTRACT The performance of screw feeders is affected by the design of their three major components (hopper, screw casing and screw), the rotational speed of the screw, the inclination of the screw, and the properties and size... more
ABSTRACT The performance of screw feeders is affected by the design of their three major components (hopper, screw casing and screw), the rotational speed of the screw, the inclination of the screw, and the properties and size distribution of the bulk material. In this paper we focus on the application of the Discrete Element Method (DEM) to simulate the transport of granular material by screw feeders. Examples of 3D models of enclosed screw feeders are presented along with detailed predictions of their performance, namely: (1) the effect on the mass flow rate of a screw feeder as its angle of inclination was increased; (2) the effect on the mass flow rate of a screw feeder having a shaft-less screw as its inclination increased; (3) the degree to which particles of different sizes segregate as they are pushed along the screw feeder; and (4) the nature of the draw down of the bulk material from a hopper into the screw casing by the rotating screw.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
ABSTRACT The Isamill is a horizontal stirred media mill used for fine and ultrafine grinding of slurry transported rock particles. The charge motion is analysed using two different approaches, (1) a fluid only model, and (2) a 1-way... more
ABSTRACT The Isamill is a horizontal stirred media mill used for fine and ultrafine grinding of slurry transported rock particles. The charge motion is analysed using two different approaches, (1) a fluid only model, and (2) a 1-way coupled DEM + SPH model. The flow pattern when the classifier is closed is regular with a pair of oppositely oriented vortices between each pair of grinding discs. A strong radial outflow from the middle of the classifier is generated by the high centrifugal force which creates a pair of toroidal vortices at the discharge end of the mill. The classifier, when open, acts as a pump drawing slurry axially along the mill. It enters the classifier through the holes in its end plate and is then forced radially outward by rotational acceleration of the classifier cage. The enhanced outflow significantly strengthens the large toroidal vortices on the outside of the classifier. This produces a strong retrograde annular flow along the mill shell that penetrates a significant distance back into the grinding chamber. The effect of the classifier is significant and strongly influences the flow over much of the mill and controls slurry (feed and product) transport and discharge. The predictions of the different models are qualitatively similar but with important differences including the fluid only model predicting higher flow speeds because it cannot capture the strong slip between the media and the grinding discs. The strength of the axial transport is strongly dependent on the slurry viscosity. A critical viscosity can be identified above which there is insufficient axial transport to enable mill operation.
Research Interests:
Research Interests:
Research Interests:
The accuracy and stability of the classical formulation of the smoothed particle hydrodynamics (SPH) method for modelling compression of elastic solids is studied to assess its suitability for predicting solid deformation. SPH has natural... more
The accuracy and stability of the classical formulation of the smoothed particle hydrodynamics (SPH) method for modelling compression of elastic solids is studied to assess its suitability for predicting solid deformation. SPH has natural advantages for simulating problems involving compression of deformable solids arising from its ability to handle large deformation without re-meshing, complex free surface behaviour and tracking of multiple material interfaces. The ‘classical SPH method’, as originally proposed by Monaghan (in Ann Rev Astron 30:543–574, 1992, Rep Prog Phys 68:1703–1759, 2005), has become broadly established as a robust method in different areas, especially involving fluid flows. However, limited attention has been paid to understanding of its numerical performance for elastic deformation problems. To address this, we evaluate the classical SPH method to explore its stability, accuracy and convergence and the effect of numerical parameters on elastic solutions using...
Research Interests:
The patterns of rock comminution within tumbling mills, as well as the nature of forces, are of significant practical importance. Discrete element modelling (DEM) has been used to analyse the pattern of specific energy applied to rock, in... more
The patterns of rock comminution within tumbling mills, as well as the nature of forces, are of significant practical importance. Discrete element modelling (DEM) has been used to analyse the pattern of specific energy applied to rock, in terms of spatial distribution within a pilot AG/SAG mill. We also analysed in some detail the nature of the forces, which may
Research Interests:
ABSTRACT Wear prediction is important in the development and optimisation of liner design, and for helping to manage reline strategies. DEM is able to predict wear and profile evolution of liners over the life cycle for specific sets of... more
ABSTRACT Wear prediction is important in the development and optimisation of liner design, and for helping to manage reline strategies. DEM is able to predict wear and profile evolution of liners over the life cycle for specific sets of conditions. However, real operation conditions often vary – usually in ways that are not known in advance, which limits the ability to use such model predictions in managing associated wear. In this study, we use a specific case of a tumbling mill to explore issues around the variability of wear caused by different operating conditions within the applicable range for the mill, and consider how these can be included in a modelling framework in order to assist with mill liner management.
Research Interests:
ABSTRACT Full three-dimensional simulation of the impact of a rogue wave on a semi-submersible platform is undertaken using the Smoothed Particle Hydrodynamics (SPH) technique. Two different mooring configurations are considered: A... more
ABSTRACT Full three-dimensional simulation of the impact of a rogue wave on a semi-submersible platform is undertaken using the Smoothed Particle Hydrodynamics (SPH) technique. Two different mooring configurations are considered: A Tension Leg Platform (TLP) system and a Taut Spread Mooring (TSM) system. It is seen that for a wave impact normal to the platform side, the heave and surge responses of the platform are significantly different for the two mooring systems. The TLP system undergoes large surge but comparatively smaller heave motions than the TSM system. The degree of pitch is very similar. The total tension in the mooring cables is approximately four times higher in the TSM system and exceeds the strength of the cables used in the simulation. SPH is seen to be an attractive alternative to standard methods for simulating the coupled interaction of highly non-linear breaking waves and structural motion.
Research Interests:
Research Interests:
Research Interests:
Discrete element modelling (DEM) of granular ows involves following the trajec-tories and spins of all the particles and objects in the system and predicting their interactions with other particles and with their environment. It is... more
Discrete element modelling (DEM) of granular ows involves following the trajec-tories and spins of all the particles and objects in the system and predicting their interactions with other particles and with their environment. It is necessary to sim-ulate particles of many di erent sizes and densities interacting with complex shaped objects moving in a range of di erent ways. The key ingredients are a fast and robust algorithm to predict collisions, a good collision model and an e cient and powerful method for describing the objects. Campbell [3] provides a good review of the area.