The song of the Dunes - Collective motions in a Granular Flow
type: Distribution
access URL: https://theses.hal.science/tel-00770253
format: HTML
issued: 2026-05-15T13:47:46.919879
modified: 2026-05-15T13:47:46.776218

test_moissonnage_selune
type: Agent

The song of the Dunes - Collective motions in a Granular Flow
type: Dataset
contact point: Organization
  fn: CCSD
keyword: acoustique
keyword: acoustic
keyword: chant
keyword: granulaire
keyword: avalanche
keyword: flow
keyword: synchronisation
keyword: ecoulement
keyword: spiacouengineering-sciences-physicsacoustics-physicsclass-ph
keyword: granular
keyword: physcondcm-scmphysics-physicscondensed-matter-cond-matsoft-condensed-matter-cond-matsoft
keyword: theses
keyword: physphysphys-flu-dynphysics-physicsphysics-physicsfluid-dynamics-physicsflu-dyn
keyword: booming
keyword: infoeu-reposemanticsdoctoralthesis
keyword: dune
keyword: physmecaacouphysics-physicsmechanics-physicsacoustics-physicsclass-ph
keyword: surface
keyword: singing
landing page: https://theses.hal.science/tel-00770253
description: The song of dunes is a natural phenomenon that have arisen men's curiosity for a long time, from Marco Polo to R.A. Bagnold. Scientific observations in the XXth century have shown that the sound is emitted by a coherent vibration of the free surface of a flow in these special singing grains, and that this sound is linked to a threshold effect that depends on many parameters. In order to understand the synchronization mechanism that links the movements of the grains, we have made two missions in Morocco and in Oman to study on field these singing dunes, from which we brought back many samples. On the basis of a study of their microscopic properties, we showed that these grains are covered by a varnish that increases their friction and adhesion properties. In an experiment with varying shear rate, we characterized the threshold dependency on relative humidity as well as on flow parameters. In an avalanche experiment, we reproduced with high fidelity the song of dunes that can be heard on field and our observations showed that the flow has a part at the surface where the velocity is homogeneous like a solid movement. This experiment also showed that the synchronization is not due to an acoustic wave propagating inside the granular layer. We then developed a model based on the interaction between the force chains in the shear part of the flow and the plug part of the flow. This model have a good quantitative agreement with the experiments, and it also explains all the qualitative observations that have been made on this subject.
identifier: NNT: 2010PA077081
issued: 2026-05-15T13:47:46.821804
language: fr
modified: 2026-05-15T13:47:46.821809