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Singular behaviors in drop impacts
Christophe JosserandInst. D’Alembert, CNRS-UPMC,
Paris-France
Outline
Drop impacts dynamics form or stand numerous different singularities
Outline
Drop impacts dynamics form or stand numerous different singularities
Formation of intense jets, bubble entrapments
Outline
Drop impacts dynamics form or stand numerous different singularities
Formation of intense jets, bubble entrapments
pressure field produced by the impact
Outline
Drop impacts dynamics form or stand numerous different singularities
Formation of intense jets, bubble entrapments
pressure field produced by the impact
singular boundary layers
Outline
Impact on hydrophobic surface
Bartolo, Josserand and Bonn, PRL 96, 124501 (2006)
(a)
(b)
Bubble collapseDuchemin, Popinet, Josserand and Zaleski, POF 14, 3000-3008 (2002)
Pressure field: numerical simulation
Pressure field at short time?
Self-similar structure can be identified
Pressure impact theory
Pressure decreases like 1/Sqrt(t)
Parabolic profile near the center
Pressure impact decreases dramatically for large time as expected by the theory
Film thin equation in cylindrical geometry
Pressure field near the bottom
deviates the velocity field from vertical to horizontal directions
self-similar zone of deviation with intersection radius
P(r, t)ρU2
0=
R0√2R0U0t! r2
Pressure peak near the edge --> boundary layer?
Impact on thin liquid film
Splahs-spreading transition: Influence of the viscosity
We!
Re
Splahs-spreading transition: Influence of the viscosity
We!
Re
Viscous boundary layer near the edge
high pressure peak and vorticity creation
balance between ejection of liquid through the thin liquid sheet and capillary retraction
jet velocity scales like squareroot of the Reynolds number
S.T. Thoroddsen, JFM 451, 373 (2002)