Seminars

PMMH’s weekly seminar is held every Friday at 11 am (map)

Contact :
Alice Pelosse
Stéphane Perrard
Etienne Reyssat
Virgile Thiévenaz
responsables-seminaires (arobase) pmmh.espci.fr

PMMH
BARRE CASSAN
BAT A 1ER ETAGE CASE 18
7 QUAI SAINT BERNARD
75005 PARIS
France

Tel : (33) 1 40 79 45 22


Séminaire PMMH – Emmanuel Villermaux (IRPHÉ, Marseille)

Vendredi 6 février de 11h00 à 12h00 - Salle réunion PMMH 1

Fragmentation with, and without mechanism : Are principles enough ?

When it comes to understand how a cohesive object breaks-up, there are two types of temptations : either seek for detailed mechanisms (capillary instabilities for liquids, cracks propagation in brittle solids...), or rely on a general principle to infer the multiplicity of the fragments sizes. Microscopic descriptions often overlook the question of the sizes distribution, and the uncontrolled use of conservation principles leads to notorious mistakes (see §11 in JFM 898, P1, 2020).

I will show that an original conservation law coupled with a maximal randomness principle provides new, unifying predictions. I will explain when this principle is likely to apply, and why the fragments sizes distribution is a power law p(d) d^-β in that case, with exponent
β = D + a - π^(D/2)/2^D(D/2) ! a function of the dimensionality of the breaking object D. Examples including crushed and grinned brittle materials like solid bars, plates and shells, or cubes and spheroids, but also liquid drops and bubbles, exploding liquid shells, plastic debris in the ocean, and remnants from the cavemen industry, will be considered. The discussion is supplemented by an original experiment (https://journals.aps.org/prl/abstract/10.1103/r7xz-5d9c).

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Seminars  (11)

Information for the speakers

The audience is composed of people with rather heterogeneous backgrounds including specialists in solids, fluids, granular flows, statistical physics... so the idea is to keep your talk understandable by people not necessarily working in your field... The seminar time slot runs from 11am to noon so the best is to make the talk last around 45 minutes to leave some time for discussion.

Link to cofee seminar (internal, every Thursday)


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Contact

Directeur : Ramiro GODOY DIANA
Codirecteur : Laurent DUCHEMIN
Administratrice : Frédérique AUGER (01 40 79 45 22)
Gestionnaire : Claudette BAREZ (01 40 79 58 53)
Courriel : dir (arobase) pmmh.espci.fr
Téléphone : 01 40 79 45 22
Adresse : PMMH UMR 7636 CNRS, ESPCI Paris-PSL, Sorbonne Université, Université Paris Cité
7 Quai Saint Bernard, Barre Cassan Bât A 1er étage Case 18, 75005 Paris