Morphodynamics Of Rivers And Dunes – ZEPHYR

Morphodynamics of dunes and rivers at the grain, the object and the landscape scale. In the 80s, theoretical geomorphology was fashionable in physics by means of the see 80k for fractal exponents in natural objects (e.g., river basins, montains, shore lines). Such a community in now well established in US and Europe. In France, inspired by seminal works of C. Jaupard, the interface between physics and geophysics has been developped from an original point of view putting forward controlled lab experiments (e.g., in IPG in Paris, Géosciences in Rennes, LGIT in Grenoble, etc.). In the Morphdynamics team of PMMH, we aim at identifying and understanding, the mechanisms at work in natural phenomena: avalanches, dunes, rivers, etc. In particular, experiments and field measurements constitute an important part of these studies. They enforce a direct and necessary comparison of our ideas and models with reality. A transversal approach of geophysics.This project Zephyr is focused on problems a three differents scales: sediment transport at the grain scale, primary instabilities at the origin of elementary structures (ripples, dunes, bars, meanders), and the dynamics at the landscape scale. We have worked with controlled ans rescaled experiments, field works as well as numerical simulations. We have developped a code to describe the two way coupling between a fluid flow, described in the continuum, and grains, descibed as discrete particles. We could thenstudy the transition
between aqueous bed-load and eolian saltation. This code also enabled us to reproduce the emergence of aeolian ripples by the direct simulations.