In the present work, we use dune modeling in order to investigate the evolution of transverse dunes in the presence of vegetation. The vegetation is allowed to grow up to a maximum height Hmax with a growth rate R that oscillates in time. We find that the presence of the vegetation establishes a...

The interaction of moving fluids with particles is still only understood phenomenologically when the Reynolds number is not vanishing. I will present three different numerical studies all using the solver “fluent” which elucidate this issue from different points of view. On one hand, I will...

This brief overview is designed to introduce some of the advances that have occurred in our understanding of percolation phenomena. We organize our presentation around three simple questions: (i) What are percolation phenomena? (ii) Why do we care? (iii) What do we actually do? To answer the...

Boolean networks can be used as simple but general models for complex self-organizing systems. The freedom to choose different rules and structures of interactions makes this model applicable to a wide variety of complex phenomena. It is known that the damage dynamics in annealed Boolean systems...

We study flux penetration in a disordered type II superconductor by simulations of interacting vortices, using a Monte-Carlo method for vortex nucleation. Our results show that a detailed description of the nucleation process yields a correction to the scaling laws usually associated with flux...

Power grids, road maps, and river streams are examples of infrastructural networks which are highly vulnerable to external perturbations. An abrupt local change of load (voltage, traffic density, or water level) might propagate in a cascading way and affect a significant fraction of the network....

Brittle materials fragment when exploded or under impact. The study of fragmentation is of practical importance in many areas, ranging from archaeology to milling. In the last 10 years much progress has been achieved in the understanding of the fragment size and velocity distributions as...

We have performed computer simulations of Kauffman’s automata on several graphs, such as the regular square lattice and invasion percolation clusters, in order to investigate phase transitions, radial distributions of the mean total damage (dynamical exponent) and propagation speeds of the...

We study an iterative stochastic process as a model for two- and three-dimensional discrete fragmentation. The model fulfills mass conservation and is defined on two- and three-dimensional lattices of linear size 2n. At each step of the process the “most stressed” piece is broken in the...

We present MD simulations of shear cells of a densily packed array of polygonal grains in two dimensions. We study the dependence of the shear force on the shear velocity. Generally shear hardening is observed. The dependence of the dilatancy on the shear velocity is measured. We also apply the...