– Considering recent results revealing the existence of multi-scale rigid clusters of grains embedded in granular surface flows, i.e. flows down an erodible bed, we describe here the surface flows rheology through a non-local constitutive law. The predictions of the resulting model are compared quantitatively to experimental results: The model succeeds to account for the counter-intuitive shape...

– Inelastic grains in a flow under gravitation tend to collapse into states in which the relative normal velocities of two neighboring grains is zero. If the time scale for this gravitational collapse is shorter than inverse strain rates in the flow, we propose that this collapse will lead to the formation of “granular eddies”, large scale condensed structures of particles moving coherently wit...

and Yeh, 1996; Roth and Hammel, 1996; Birkholzer and Tsang, 1997) suggest that in unsaturated media, An infiltration and dye transport experiment was conducted to the macrodispersivity for the equivalent homogeneous visualize flow and transport processes in a heterogeneous, layered, medium, which is in general anisotropic, increases with sandy-gravelly fluvial deposit adjacent to Rio Bravo Boul...

The purpose of this communication is to discuss the simulation of a free surface compressible flow between two fluids, typically air and water. We use a two fluid model with the same velocity, pressure and temperature for both phases. In such a numerical model, the free surface becomes a thin three dimensional zone. The present method has at least three advantages: (i) the free-surface treatmen...

– In a seminal experiment, Jaeger et al. (Phys. Rev. Lett., 62 (1989) 40) measured the power spectrum of the velocity of avalanches along a granular pile in a rotating drum. Although their findings started an actively discussed debate on whether self-organized criticality rules granular avalanche dynamics, their experimental results have not been explained in theoretical detail yet. By the use ...

Aeolian sand dunes originate from wind flow and sand bed interactions. According to wind properties and sand availability, they can adopt different shapes, ranging from huge motion-less star dunes to small and mobile barchan dunes. The latter are crescentic and emerge under a unidirectional wind, with a low sand supply. Here, a 3d model for barchan based on existing 2d model is proposed. After ...

introduction: wind erosion is one of the most important factors in desert environments. prevailing winds can shift sand dunes and affect their accumulation and morphology. also, wind regime determines the direction of sand dune mobility in different ways. therefore, the wind regime, frequency, direction and velocity are supposed to be the most important factors to form the morphology of sand du...

Aeolian desert sand dunes birth from wind flow and sand bed interactions: depending on wind properties and sand availability, they can adopt several different shapes from huge motionless star dunes to small and fast mobile barchan dunes. These latter have a characteristic crescentic shape and form on hard ground with low sand supply under a monodirectional wind . Here, a 3d barchan model based ...