ESPCI web site
Séminaire Café (Interne)
Il s’agit d’un exposé assez court (20 min) et assez informel.
Prière aux conférencier·ère·s de ne jamais dépasser 30 min et de vérifier la compatibilité avec le projecteur avant le séminaire.
Les séminaires ont lieu les jeudis après la réunion du laboratoire qui débute à 13h30 dans la bibliothèque du labo sur le campus Jussieu, Barre Cassan, Bât A, 1er étage.
Pour suggérer un titre et envoyer un abstract, contacter Antoine Bouvier <
>
et Jeanne Moscatelli <
>
.
Coffee seminars are supposed to be short and informal presentations (20 min).
Please never last longer than 30 min and check the compatibility of the projector with your computer before the seminar.
Location : Campus Jussieu, Barre Cassan, Bât A, 1er étage
7 quai Saint Bernard
75005 Paris
To suggest a title or send an abstract, please contact Antoine Bouvier <>
and Jeanne Moscatelli <>
..
| 11 avril | Wladimir Sarlin Post-doc at LadHyX Water waves generated by a granular collapse : An experimental study of landslide-induced tsunamis Tsunamis are amongst the most destructive natural disasters for coastal populations around the world. Such natural disasters may be generated from massive landslides or rockfalls, for example when a volcano becomes destabilized and falls into a lake, a fjord, or even the ocean. The generation of such waves is studied here by using a model experimental configuration, in which a column of granular material of rectangular cross-section, which mimics the landslide, collapses into a quiescent water. Systematic measurements are performed, in which the depth of liquid as well as the geometry of the grains’ column are varied, in order to obtain the outcomes of the granular avalanche as well as those of the generated wave. In the experiments, different regimes are identified, including bore, solitary or Cauchy-Poisson waves. The formation of these waves is intimately related to the local Froude number, which corresponds to the ratio of the maximum horizontal velocity of the granular front to the speed of linear gravity waves in shallow water. The generated waves are non-linear in shallow water, but tend to the linear case in the deep-water limit. From there, by focusing on the dry granular collapse dynamics, the characteristic time scales involved are revealed. Finally, a model is proposed to relate the maximum amplitude of the produced wave to the initial geometrical parameters, by combining the results obtained for the dynamics of the collapse and those about the hydrodynamics of the waves in shallow water. The approach successfully compares with the experiments and explains the influence of the different key dimensionless numbers that were proposed in the literature on the subject. This constitutes a first simplified, albeit comprehensive, modelling of the physics underlying tsunamis caused by landslides in a shallow water context. The next steps of this experimental journey include the study of the three-dimensional effects, ubiquitous in real scenarios, as well as the influence of additional parameters such as the physical properties of the granular medium. |
| 18 avril | PhD student : Bérénice DUPONT, Kexin ZHANG & Nathan VANI |
| 25 avril | Krishan Bumma PhD student at Institut d’Alembert Freezing (almost) destroys soap-water foams. The solidification of disordered complex media is a challenging problem that appears in a wide range natural and industrial applications (sea ice, ground freezing, cryopreservation, food industry...). Foams are a type of complex material of particular interest for it’s industrial uses. However solidifying a foam poses distinct challenges due to the presence of gaz bubbles in the solidifying metastable fluid matrix. By placing a model aqueous foam in contact with a cold surface, we observe that, as it freezes, the foam undergoes a drastic change in volume revealing important liquid and gas migration in the foam. We quantify the liquid and the gaz flows as the foam solidifies and show that they follow non-trivial scaling laws. |
| 2 mai | Friedrich Walzel PhD student at Institut Charles Sadron (Strasbourg university) |
| 9 mai | No coffee seminar (holiday) |
| 16 mai | TBA |
| 23 mai | Kevin Matías Simpson Alfaro Post-doctorant at Pontificia Universidad Católica de Chile |
| 30 mai | Corentin Bisot PhD student at AMOLF, Amsterdam |
