190 likes | 298 Views
Dancing Particles on Faraday Wave. Ceyda Sanli , Devaraj van der Meer, and Detlef Lohse. Physics of Fluids, University of Twente. 1 st Jamming and Rheology Meeting. 26 May 2009, Leiden, The Netherlands. Set-Up. Control Parameters. particle size = D. shaking strength =.
E N D
Dancing Particles on Faraday Wave Ceyda Sanli, Devaraj van der Meer, and Detlef Lohse Physics of Fluids, University of Twente 1st Jamming and Rheology Meeting 26 May 2009, Leiden, The Netherlands
Set-Up Control Parameters • particle size = D • shaking strength = • particle concentration = ϕ • time = t
Why do we observe this transition in the pattern when increasing ϕ? Why nodes at high ϕ? A N N HIGH ϕ: to nodes LOW ϕ: to antinodes INTERMEDIATE ϕ • For low ϕ, hydrophobic particles go to antinodes.* * G. Falkovichet al. Nature 435, 1045 (2005).
Force without shaking * Chan, et. al. J. Colloid Interface Sci. 79, 410 (1981). D = 1.5 mm D = 3.2 mm capillary - gravity collective effects
Competition between forces no shaking L (weak) L ~ λ at L ~ D + shaking (strong)
Clustering at antinode ϕ = 0.032 N t = 10 min. N N A N f = 28.25 Hz a = 0.04 mm 10 mm
Clustering at node A ϕ = 0.83 t = 7 min. N 10 mm
What happens at intermediate density? ϕ 0 1 0.032 0.83 0.47 antinode clusters node clusters ?
Transient effects t = 58 min: Metastablepattern ϕ = 0.47 10 mm
Pattern after 88 min. ϕ = 0.47 10 mm
Final pattern after 150 min. ϕ = 0.47 10 mm
ϕ Time dependent picture of patterns ϕ * (middle area) = ϕ (one experiment) (full area) preliminary result! fixed value square 2 circle ? final pattern 1.5 ϕ * 1 0.5 0 25 50 75 100 125 150 t (min.)
Conclusion • Clusteringbehavior is changed by increasing number of particles. • Competition:Clustering at antinodeClustering at node low ϕ high ϕ • Even though p-p interaction is small comparing to the drift force, • the many-body interaction drives another dominant force for high ϕ. • Extremely long transient dynamics revealed at intermediateϕ.