ESPCI web site
PMMH’s weekly seminar is held every Friday at 11 am (map)
Stéphane Perrard
Etienne Reyssat
Virgile Thiévenaz
PMMH
BARRE CASSAN
BAT A 1ER ETAGE CASE 18
7 QUAI SAINT BERNARD
75005 PARIS
France
Tel : (33) 1 40 79 45 22
Séminaire : Pierre-Thomas Brun (EPFL)
From the Viscous Sewing Machine to the Cowboy's Lasso
Part I : The fluid mechanical sewing machine
A thin thread of viscous fluid falls onto a moving conveyer belt and lays down in a plethora of complex "stitch" patterns depending on the belt speed and the height of fall. This experiment is well documented in the literature and we used direct numerical simulations to reproduce and investigate the typical yet unexplained patterns. In particular the Fourier analysis of the motion of the thread's contact point with the belt suggests a new classification of these patterns patterns. Indeed, they result from the combination of simple ratios of the natural frequency of the thread \Omega_c. Of particular interest is the alternating loops pattern witch frequencies are locked on the first five multiple of \Omega_c/3. Furthermore, we built up on these observations to propose a toy model for such a complex system.
Part II : The lasso
How does a cowboy manage to form a flat loop when spinning a lasso in the air ? and why is so difficult to realize such a trick ? Trick roping is an art derived from the original ability of Mexican Charros and American Cowboys to catch cattle. Of particular interest for us is the mathematical scaffold upon which trick roping is built. We combine analytics (continuation and matched asymptotics) with experiments to build up a representative model of the lasso that ultimately provides a recipe to successfully realize basic rope tricks.
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.
- Séminaires ESPCI-ENS de biophysique
- Séminaires du Département de Physique de l’ENS
- Séminaires du Laboratoire d’Hydrodynamique de l’X
- Séminaire de Mécanique d’Orsay (page web FAST)
- Séminaire de Mécanique d’Orsay (page web LIMSI)
- Séminaire de Mécanique des Fluides de l’Institut Jean le Rond d’Alembert
- Séminaires du laboratoire MSC, Paris VII
- Séminaires Gulliver
Link to cofee seminar (internal, every Thursday)
