We use high-speed video imaging to study the capillary-driven motion of a micro-droplet along the outside of a pre-wetted conical fiber. The cones are fabricated on a glass-puller with tip diameters as small as 1 μm, an order of magnitude smaller than in previous studies. The liquid is fed through the hollow fiber accumulating at the fiber tip to form droplets. The droplets are initially attached to the opening as they grow in size before detaching and traveling up the cone. This detachment can produce a transient oscillation of high frequency. The spatial variation of the capillary pressure drives the droplets towards the wider side of the cone. Various liquids were used to change the surface tension by a factor of 3.5 and viscosity by a factor of 1500. Within each droplet size and viscous-dissipation regime, the data for climbing speeds collapse on a single curve. Droplets traveling with and against gravity allow us to pinpoint the absolute strength of the driving capillary pressure and viscous stresses and thereby determine the prefactors in the dimensionless relationships. The motions are consistent with earlier results obtained from much larger cones. Translation velocities up to 270 mm/s were observed and overall the velocities follow capillary-viscous scaling, whereas the speed of the fastest droplets is limited by inertia following their emergence at the cone tip.
Skip Nav Destination
Article navigation
Research Article|
May 21 2013
The fastest drop climbing on a wet conical fibre
Er Qiang Li;
Er Qiang Li
1Division of Physical Sciences and Engineering,
King Abdullah University of Science and Technology (KAUST)
, Thuwal 23955-6900, Saudi Arabia
Search for other works by this author on:
Sigurdur T. Thoroddsen
Sigurdur T. Thoroddsen
a)
1Division of Physical Sciences and Engineering,
King Abdullah University of Science and Technology (KAUST)
, Thuwal 23955-6900, Saudi Arabia
2Clean Combustion Research Center,
King Abdullah University of Science and Technology (KAUST)
, Thuwal 23955-6900, Saudi Arabia
Search for other works by this author on:
a)
Author to whom correspondence should be addressed. Electronic mail: sigurdur.thoroddsen@kaust.edu.sa.
Physics of Fluids 25, 052105 (2013)
Article history
Received:
December 22 2012
Accepted:
April 12 2013
Citation
Er Qiang Li, Sigurdur T. Thoroddsen; The fastest drop climbing on a wet conical fibre. Physics of Fluids 1 May 2013; 25 (5): 052105. https://doi.org/10.1063/1.4805068
Download citation file:
Sign in
Don't already have an account? Register
Sign In
You could not be signed in. Please check your credentials and make sure you have an active account and try again.
Pay-Per-View Access
$40.00
Citing articles via
On Oreology, the fracture and flow of “milk's favorite cookie®”
Crystal E. Owens, Max R. Fan (范瑞), et al.
A unified theory for bubble dynamics
A-Man Zhang (张阿漫), 张阿漫, et al.
Computational fluid–structure interaction in biology and soft robots: A review
R. Pramanik, R. W. C. P. Verstappen, et al.
Related Content
The fastest capillary flow under gravity
Appl. Phys. Lett. (June 2014)
The dynamic behavior of a self-propelled droplet on a conical fiber: A lattice Boltzmann study
Physics of Fluids (August 2023)
Equilibrium and stability of axisymmetric drops on a conical substrate under gravity
Physics of Fluids (August 2015)
Bubble growth by injection of gas into viscous liquids in cylindrical and conical tubes
Physics of Fluids (October 2011)
The influence of inertia and contact angle on the instability of partially wetting liquid strips: A numerical analysis study
Physics of Fluids (March 2014)