Informal workshop on Foam mechanics, Grenoble, 21st - 27th January 2008

Information for participants

Scientific Interactions Travel Accommodation/Subsistence Preparation Questions Publications Participants

Discussion notes are here

Photos of the scheduling whiteboard are here

Scientific interactions

• This workshop will be as successful as you make it! So please come with ideas (for science, for discussions, for interactions, for experiments, for restaurants, ...).
• From Monday to Friday we will organise a debate at 11:30, led by one of the participants. In addition, on Monday afternoon Michael Dennin will give a lab seminar. These are the only events that are scheduled in advance. Due to the availability of participants the debates may not follow a strictly logical sequence.
• We also propose sessions in which participants may briefly present new results, contentious or open questions, ideas, ... The format for this is that we will post a sign-up sheet for each day a little in advance. Each presentation will consist of 5 minutes (using a white/blackboard and/or one overhead transparency), followed by 5 minutes of questions and discussion.
• All other time will be devoted to self-organised interaction, in pairs, small groups, or whatever (and wherever) you decide is most useful. You can choose to organise private discussions, public discussions, tutorials (ask someone to do it), journal club; the only rule is: "no computer projector". We will provide a (large) chart where you can announce and schedule these (giving subject, room and participants).
• We encourage people to (i) take a few lines of notes to record the essence of any public discussion, and (ii) to be sympathetic towards the participation of (usually) shy people.
• On Saturday and Sunday we will not organise anything. We anticipate that people (skiers and non-skiers alike) may wish to continue discussions in the mountains.

To get to the Lab Spectrometrie Physique, Universite Joseph Fourier

• There are detailed instructions with maps in English or French.
• By tram: take tram B (e.g. from the station) or C and get off at the stop Gabriel Faure. Retrace your route for 20m, cross the tracks, and the lab (Spectrometrie Physique) is the second building on your left. You should buy (and stamp) your ticket before entering the tram.
• You can hire a bicycle at the station or on campus (MetroVelo).
• Access to the lab requires a badge: people who want one must give a deposit of 15 euros; otherwise you should use the access phone next to door number 1 (call Mme J. Sitbon or Mme S. Gustave and mention the workshop) or wait for somebody else to enter.

To get to Grenoble

• Paris - 3h or 4h by train, a few trains a day, 150 euros round trip.
• Lyon, Aeroport St Exupery - 1h by shuttle bus, each hour, 30 euros round trip (cheaper than two singles).
• Geneva Airport - 2h or 3h by train, a few trains a day, around 40 euros round trip
• Chambery Airport (a few low cost airlines) - 45 mins by train, very frequent, around 20 euros round trip.
• Grenoble Airport (a few low cost airlines) - 30 mins by shuttle bus, normally meeting the plane (check in advance), around 15 euros round trip.

Accommodation

• Information about hotels from l'Office du Tourisme in Grenoble.
• ResidHotel Central Gare and ResidHotel Le Royal are appartments with a small kitchenette.
• Residence Rive Droite, is similar, but more basic (and cheaper).
• Hotel Moucherotte is a 1*,Hotel de l'Europe a 2* hotel, and Hotel d'Angleterre a 3* hotel, all in convenient locations.
• The auberge de jeunesse (Youth Hostel) in Grenoble is very welcoming, but not very convenient by public transport.

Meals

Prepare yourself

• Please bring one copy of each of your preprints to be made available for discussion and browsing.
• Please note that we do not anticipate that it will be easy for people to use the internet at the lab.
• Polish your skis :-)

Questions to think about

• 2 Dimensions versus 3 Dimensions: Common points and differences. Microfluidics. Effect of walls. Friction, slip. Boundary conditions
• Acoustics : Propagation. Measurements. Manipulation of bubbles.
• Constitutive equation: Relation with other materials. Scalars and matrices. Objective derivatives. Definitions and measurements of strain. Role of fluctuations. Non-monotonous constitutive equation. Role of past history. Models. Soft glassy rheology.
• Coupling with drainage: Relative motion of liquid and gas. Poroelasticity. Dilatancy. Convective instability. Static and dynamic definitions of liquid fraction.
• Instabilities : Preemptive. Convective. High speed. Fracture. Shear banding. Size segregation.
• Others : beer, wine, ski. OpenOffice.
• Role of material properties: Surfactants. Liquid fraction. Disorder. Particles. Initial stresses.
• Screening: Range of influence (and propagation) of a T1, of a T2, of a bubble's volume change, of a dislocation. Laser-induced breakage of a bubble. Role of disorder. Avalanches. Long-range correlations. From discrete to continuous description. Size of representative volume element.
• Simulations : reconciling Potts and Evolver. Multi-scale modelling, Bubble and Vertex Models, Navier-Stokes. Possibilities and limits. Short and long range interactions between bubbles.
• Space variation: Localisation, shear banding. Fluctuations. Place of occurrence of T1s. Size segregation.
• Tutorials : General presentation of motivations, state of the art, open questions. Experimental and numerical methods. Surface viscoelasticity.
• Yielding: Definition and measurement. Yield stress (distinguish dynamic and static) and yield strain. Role of disorder, of liquid fraction, of shear direction. Progressive yielding. Topological changes : T1s and T2s. Their location and orientation in a shear flow. Weak and strong regions. Reversibility and irreversibility. Overshoot. Strain hardening
• Visco-elasticity: Storage (G') and loss (G") moduli. High and low frequency values. Harmonics, non-linearities. Effective viscosity. Time scales. Physical mechanisms at the scale of bubbles. Comparison with bulk liquid viscosity. Zero-frequency shear modulus. Role of disorder. Compression.

Publications

List of Participants

Simon's Bit