Download presentation

Presentation is loading. Please wait.

Published byOctavio Vercoe Modified over 3 years ago

1
J.E. Sprittles (University of Birmingham / Oxford, U.K.) Y.D. Shikhmurzaev(University of Birmingham, U.K.) Seminar at KAUST, February 2012

2
‘Impact’ A few years after completing my PhD.....

3
Wetting: Statics Non-Wettable (Hydrophobic) Wettable (Hydrophilic)

4
Wetting: Dynamics

5
Capillary Rise 50nm x 900nm Channels Han et al 06 27mm Radius Tube Stange et al 03 1 Million Orders of Magnitude!!

6
Polymer-Organic LED (P-OLED) Displays

7
Inkjet Printing of P-OLED Displays Microdrop Impact & Spreading

8
Modelling: Why Bother? 1 - Recover Hidden Information 2 - Map Regimes of Spreading 3 – Experiment Millimetres in Milliseconds - Rioboo et al (2002) Microns in Microseconds - Dong et al (2002) Flow Inside Solids – Marston et al 2010

9
r Pasandideh-Fard et al 1996 Dynamic Contact Angle Required as a boundary condition for the free surface shape. r t

10
Speed-Angle Formulae R σ1σ1 σ 3 - σ 2 Young Equation Dynamic Contact Angle Formula ) U Assumption: A unique angle for each speed

11
Drop Impact Experiments ) Bayer & Megaridis 06

12
Capillary Rise Experiments Sobolev et al 01

14
Physics of Dynamic Wetting Make a dry solid wet. Create a new/fresh liquid-solid interface. Class of flows with forming interfaces. Forming interface Formed interface Liquid-solidinterface Solid

15
Relevance of the Young Equation R σ 1e σ 3e - σ 2e Dynamic contact angle results from dynamic surface tensions. The angle is now determined by the flow field. Slip created by surface tension gradients (Marangoni effect) θeθe θdθd Static situationDynamic wetting σ1σ1 σ 3 - σ 2 R

16
In the bulk: On liquid-solid interfaces: At contact lines: On free surfaces: Interface Formation Model θdθd e2e2 e1e1 n n f (r, t )=0 Interface Formation Modelling

17
JES &YDS 2011, Viscous Flows in Domains with Corners, CMAME JES & YDS 2012, Finite Element Framework for Simulating Dynamic Wetting Flows, Int. J. Num. Meth Fluids. JES & YDS, 2012, Finite Element Simulation of Dynamic Wetting Flows as an Interface Formation Process, to JCP. JES & YDS, 2012, The Dynamics of Liquid Drops and their Interaction with Surfaces of Varying Wettabilities, to PoF.

18
Mesh Resolution Critical

19
Arbitrary Lagrangian Eulerian Mesh Control

21
Impact at Different Scales Millimetre Drop Microdrop Nanodrop

22
Pyramidal (mm-sized) Drops Experiment of Renardy et al, 03.

23
Microdrop Impact 25 micron water drop impacting at 5m/s on left: wettable substrate right: nonwettable substrate

24
Microdrop Impact Velocity Scale Pressure Scale

25
Microdrop Impact ?

26
Hidden Dynamics

27
Surfaces of Variable Wettability 1 1.5

28
Flow Control on Patterned Surfaces JES & YDS 2012, to PoF

30
Steady Propagation of a Meniscus

31
Flow Characteristics

32
‘Hydrodynamic Resist’ Smaller Capillaries

33
Washburn Model Basic Dynamic Wetting Models Interface Formation Model and Experiments Equilibrium Dynamic Equilibrium Dynamic Equilibrium Dynamic Meniscus Meniscus shape unchanged by dynamic wetting Meniscus shape dependent on speed of propagation. Hydrodynamic Resist: Meniscus shape influenced by geometry Summary: Dynamic Wetting Models

34
Capillary Rise: Models vs Experiments Compare to experiments of Joos et al 90 and conventional Lucas-Washburn theory Lucas-Washburn assumes: Poiseuille Flow Throughout Spherical Cap Meniscus Fixed (Equilibrium) Contact Angle

35
Lucas-Washburn vs Full Simulation R = 0.036cm; every 100secs R = 0.074cm; every 50secs

36
Comparison to Experiment Full Simulation Washburn JES & YDS 2012, to JCP

37
Wetting as a Microscopic Process: Flow through Porous Media

38
Problems and Issues

39
Micro: Pore scale dynamics of: Menisci in wetting front Ganglia Macro (Darcy-scale) dynamics of: Entire wetting front Ganglia in multiphase system Multi-scale porosity: Motion on a microporous substrate

40
Physical Reality

41
Kinematic boundary condition Dynamic boundary condition ? Continuum Model Simplest Case First: Full Displacement (no ganglia formation)

42
Wetting mode Threshold mode Wetting Front: Modes of Motion

43
1). T. Delker, D. B. Pengra & P.-z. Wong, Phys. Rev. Lett. 76, 2902 (1996). 2). M. Lago & M. Araujo, J. Colloid & Interf. Sci. 234, 35 (2001). Some Unexplained Effects ) z g

44
Suggested Description 2/3 of height in 2 mins ) z g Washburnian Non- Washburnian 1/3 of height in many hours ) )

45
Developed Theory YDS & JES 2012, JFM; YDS & JES 2012, to PRE ) z g Random Fluctuations ‘Break’ Threshold Mode

46
Flow over a Porous Substrate

47
Wetting: Micro-Macro Coupling Spreading on a Porous Medium

48
Current State of Modelling 1) Contact Line Pinned 2) Shape Fixed as Spherical Cap

49
The Reality Equilibrium shape is history-dependent.

50
Spreading on a Porous Substrate θDθD θwθw U θdθd

51
No equilibrium angle to perturb about Final shape is history dependent Approach Use continuum limit (separation of scales) Consider flow near contact line Find contact angles as a result: θDθD θwθw U YDS & JES 2012, to JFM

52
Flow Transition Formula is when contact lines coincide Example: Transition when

53
Potential Collaboration Drop Impact Microdrops on impermeable surfaces Drops on permeable/patterned surfaces Capillary Rise Investigation of ‘resist’ mechanism in micro/nano regimes Flow with Forming/Disappearing Interfaces Coalescence, bubble detachment, jet break-up, cusp-formation, etc. Porous Media Investigation of newly developed model

55
Wetting: Statics

56
) Young Laplace Contact Line Contact Angle

57
Wetting: Statics

58
Wetting: Dynamics

59
Wetting: As a Microscopic Process Macroscale Microscale Meniscus Capillary tube Wetting front

60
) Dynamics: Classical Modelling Incompressible Navier Stokes Stress balance Kinematic condition No-Slip Impermeability Angle Prescribed No Solution!

61
L.E.Scriven (1971), C.Huh (1971), A.W.Neumann (1971), S.H. Davis (1974), E.B.Dussan (1974), E.Ruckenstein (1974), A.M.Schwartz (1975), M.N.Esmail (1975), L.M.Hocking (1976), O.V.Voinov (1976), C.A.Miller (1976), P.Neogi (1976), S.G.Mason (1977), H.P.Greenspan (1978), F.Y.Kafka (1979), L.Tanner (1979), J.Lowndes (1980), D.J. Benney (1980), W.J.Timson (1980), C.G.Ngan (1982), G.F.Telezke (1982), L.M.Pismen (1982), A.Nir (1982), V.V.Pukhnachev (1982), V.A.Solonnikov (1982), P.-G. de Gennes (1983), V.M.Starov (1983), P.Bach (1985), O.Hassager (1985), K.M.Jansons (1985), R.G.Cox (1986), R.Léger (1986), D.Kröner (1987), J.-F.Joanny (1987), J.N.Tilton (1988), P.A.Durbin (1989), C.Baiocchi (1990), P.Sheng (1990), M.Zhou (1990), W.Boender (1991), A.K.Chesters (1991), A.J.J. van der Zanden (1991), P.J.Haley (1991), M.J.Miksis (1991), D.Li (1991), J.C.Slattery (1991), G.M.Homsy (1991), P.Ehrhard (1991), Y.D.Shikhmurzaev (1991), F.Brochard-Wyart (1992), M.P.Brenner (1993), A.Bertozzi (1993), D.Anderson (1993), R.A.Hayes (1993), L.W.Schwartz (1994), H.-C.Chang (1994), J.R.A.Pearson (1995), M.K.Smith (1995), R.J.Braun (1995), D.Finlow (1996), A.Bose (1996), S.G.Bankoff (1996), I.B.Bazhlekov (1996), P.Seppecher (1996), E.Ramé (1997), R.Chebbi (1997), R.Schunk (1999), N.G.Hadjconstantinou (1999), H.Gouin (10999), Y.Pomeau (1999), P.Bourgin (1999), M.C.T.Wilson (2000), D.Jacqmin (2000), J.A.Diez (2001), M.&Y.Renardy (2001), L.Kondic (2001), L.W.Fan (2001), Y.X.Gao (2001), R.Golestanian (2001), E.Raphael (2001), A.O’Rear (2002), K.B.Glasner (2003), X.D.Wang (2003), J.Eggers (2004), V.S.Ajaev (2005), C.A.Phan (2005), P.D.M.Spelt (2005), J.Monnier (2006) ‘Moving Contact Line Problem’

63
Periodically Patterned Surfaces No slip – No effect.No slip – No effect.

64
Interface Formation vs MDS Solid 2 less wettable Qualitative agreement JES & YDS 2007, PRE; JES &YDS 2009 EPJ

65
g external pressure h (t ) An Illustrative Example YDS & JES 2012, JFM

Similar presentations

OK

HDR J.-R. de Dreuzy Géosciences Rennes-CNRS. PhD. Etienne Bresciani (2008-2010) 2 Risk assessment for High Level Radioactive Waste storage.

HDR J.-R. de Dreuzy Géosciences Rennes-CNRS. PhD. Etienne Bresciani (2008-2010) 2 Risk assessment for High Level Radioactive Waste storage.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Download ppt on trigonometric functions for class 11 Ppt on ideal gas law worksheet Ppt on viruses and anti viruses name Ppt on electricity generation from municipal solid waste Ppt on 2 stroke ic engine parts Ppt on natural and manmade disaster Ppt on ms-excel functions Ppt on producers consumers and decomposers 3rd Ppt on human resource management system project Ppt on open source technology