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Ruissellement avec effets de mouillage:
Gouttes et méandres sur un plan incliné

Abstract : Under partially wetting conditions, the rear of drops sliding down an inclined plane develops, above a critical velocity, a cornered singularity which is rounded at small scale. The inclination or the curvature of the contact line delays the wetting transition. At higher velocities, a liquid rivulet, whose width increases with the velocity of the drops, develops and breaks into smaller drops deposited on the substrate. A lubrication model accurately describes several aspects of these phenomena: conical interface, delaying of the dewetting transition, width of the rivulet...
If the flow rate is increased, the liquid flows as a straight rivulet and above a critical flow rate, it destabilizes into stationary meanders. The balance between inertia, line tension and hysteresis of wetting gives the radius of curvature of the meanders, as well as the onset of meandering. The very strong flow rate hysteresis observed can be explained by pinning on the solid surface. An increase in viscosity changes the behavior of the meanders: they no longer arise spontaneously and their amplitude increases with the distance to the nozzle. These meanders with hysteresis have been compared to meanders without hysteresis, under totally wetting conditions, enclosed in a Hele-Shaw cell. Without pinning forces, the latter are therefore mobile. A few physico-chemical effects have been studied and revealed that surfactants are not necessary for meandering. A balance between inertia and capillarity gives the onset of these totally wetting meanders.
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Submitted on : Tuesday, July 4, 2006 - 4:50:12 PM
Last modification on : Friday, August 5, 2022 - 11:54:10 AM
Long-term archiving on: : Tuesday, September 18, 2012 - 4:01:02 PM


  • HAL Id : tel-00083935, version 1


Nolwenn Le Grand-Piteira. Ruissellement avec effets de mouillage:
Gouttes et méandres sur un plan incliné. Dynamique des Fluides [physics.flu-dyn]. Université Paris-Diderot - Paris VII, 2006. Français. ⟨tel-00083935⟩



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