Interactive applications such as virtual reality systems have become popular in recent years. A ground surface composed of a granular material can be deformed when it comes into contact with an object, and, in this paper, we propose a deformation algorithm for the ground surface which is useful for such applications. The deformation algorithm is divided into three steps: (1) detection of the co...

The effective phase change from fluid behaviour to solid behaviour, that too often occurs in granular flow and brings with it such unwelcome events as funnel flows in hoppers and clogging of other material handling devices, is studied using a discrete particle computer simulation of a Couette flow with gravity. This simulation exhibits the full range of granular flow behaviour, from a stagnant ...

C. G. Johnson, J. M. N. T. Gray (2010), J. Fluid Mech., (Submitted) • “Weak, strong and detached oblique shocks in gravity driven granular free-surface žows”, J. M. N. T. Gray, X. Cui (2007), J. Fluid Mech., 579, 113–136 • “Dežecting dams and the formation of oblique shocks in snow avalanches at Flateyri, Iceland”, X. Cui, J. M. N. T. Gray, T. Johannesson (2007), J. Geophys. Res., 112, F04012 •...

Despite their very low surface gravities, the surfaces of asteroids and comets are covered by granular materials regolith that can range from a fine dust to a gravellike structure of varying depths. Understanding the dynamics of granular materials is, therefore, vital for the interpretation of the surface geology of these small bodies and is also critical for the design and/or operations of any...

Changes in the structure of the nucleolus during the cell cycle of the Chinese hamster cell in vitro were studied. Quantitative electron microscopic techniques were used to establish the size and volume changes in nucleolar structures. In mitosis, nucleolar remnants, "persistent nucleoli," consisting predominantly of ribosome-like granular material, and a granular coating on the chromosomes wer...

Particle crushing dominates the deformation behaviour of granular materials under significantly high compressive and shear stress. A proposed constitutive model has been verified to predict crushing behaviour of granular materials with different crushability and adopted one kind of reference crushing stress. It is noted that no positive dilatancy of granular material in triaxial test occurs onc...

Legged robots have a long way to go before they can attain the speed and control exhibited by living organisms, especially on granular surfaces. Granular materials exhibit a wide range of material properties and can behave as solids, gases, liquids, or glasses depending on the applied stress. Adapting to such a shape-shifting base exceeds the capability of most robots. Chen Li et al. conducted ...

Visual simulation of natural erosion on terrains with granular matter, like sand, soil or gravel has been a fascinating research topic in the field of computer graphics for a long time. Ability of a fluid to drastically change internal structure or external shape of terrain is an important effect in nature. While there are many particle based algorithms to improve process of terrain erosion, on...

The Mohr-Coulomb theory of strength identifies cohesion and internal friction as the two principal contributions to the shear strength of a granular material. The contribution of cohesion in over-compacted granular materials has been challenged and replacing cohesion with interlocking has been proposed. A theory of rupture strength that includes interlocking is derived herein. The physics-chemi...

Sound and pressure wave propagation in a granular material is of interest not only for its intrinsic and practical value, but also because it provides a non-intrusive means of probing the state of a granular material. By examining wave speeds and attenuation, insight can be gained into the nature of the contacts between the particles. In the present paper, wave speeds and attenuation rates are ...