Investigating the radial spreading behavior of superimposed liquid drops

Scilight ◽  
2018 ◽  
Vol 2018 (4) ◽  
pp. 040003
Author(s):  
Meeri Kim
Author(s):  
Young-Gil Park ◽  
Anthony M. Jacobi

A numerical study was conducted on the spreading behavior of liquid drops on flat solid surfaces. The model predicts the shape of liquid-vapor interface under static equilibrium using an unstructured surface grid composed of triangular elements. Incremental movement of base contour, i.e. solid-liquid-vapor contact line, is also captured such that the constrained boundary conditions, i.e. advancing and receding contact angles, can be satisfied. The numerical model is applied to a common experiment that studies the behavior of liquid drops on inclined surfaces, where the shape of the drops change in response to an alteration of total volume or gravitational direction. On a heterogeneous surface that has contact angle hysteresis, the shape of the base contour on the solid surface is not determined uniquely but rather dependent upon history. This study demonstrates such dependence by comparing the spreading of a liquid drop on a solid surface with different quasi-equilibrium paths.


2020 ◽  
Author(s):  
K. Yu. Arefyev ◽  
O. V. Guskov ◽  
A. N. Prokhorov ◽  
A. S. Saveliev ◽  
E. E. Son ◽  
...  

Nature ◽  
2021 ◽  
Vol 592 (7855) ◽  
pp. E12-E12
Author(s):  
Robert D. Deegan ◽  
Olgica Bakajin ◽  
Todd F. Dupont ◽  
Greg Huber ◽  
Sidney R. Nagel ◽  
...  
Keyword(s):  

CORROSION ◽  
10.5006/0611 ◽  
2013 ◽  
Vol 69 (5) ◽  
pp. 468-476 ◽  
Author(s):  
Mattias Forslund ◽  
Christofer Leygraf ◽  
Changjian Lin ◽  
Jinshan Pan

2009 ◽  
Vol 626 ◽  
pp. 367-393 ◽  
Author(s):  
STEFAN MÄHLMANN ◽  
DEMETRIOS T. PAPAGEORGIOU

The effect of an electric field on a periodic array of two-dimensional liquid drops suspended in simple shear flow is studied numerically. The shear is produced by moving the parallel walls of the channel containing the fluids at equal speeds but in opposite directions and an electric field is generated by imposing a constant voltage difference across the channel walls. The level set method is adapted to electrohydrodynamics problems that include a background flow in order to compute the effects of permittivity and conductivity differences between the two phases on the dynamics and drop configurations. The electric field introduces additional interfacial stresses at the drop interface and we perform extensive computations to assess the combined effects of electric fields, surface tension and inertia. Our computations for perfect dielectric systems indicate that the electric field increases the drop deformation to generate elongated drops at steady state, and at the same time alters the drop orientation by increasing alignment with the vertical, which is the direction of the underlying electric field. These phenomena are observed for a range of values of Reynolds and capillary numbers. Computations using the leaky dielectric model also indicate that for certain combinations of electric properties the drop can undergo enhanced alignment with the vertical or the horizontal, as compared to perfect dielectric systems. For cases of enhanced elongation and alignment with the vertical, the flow positions the droplets closer to the channel walls where they cause larger wall shear stresses. We also establish that a sufficiently strong electric field can be used to destabilize the flow in the sense that steady-state droplets that can exist in its absence for a set of physical parameters, become increasingly and indefinitely elongated until additional mechanisms can lead to rupture. It is suggested that electric fields can be used to enhance such phenomena.


1975 ◽  
Vol 71 (2) ◽  
pp. 361-383 ◽  
Author(s):  
B. P. Ho ◽  
L. G. Leal

The creeping motion through a circular tube of neutrally buoyant Newtonian drops which have an undeformed radius comparable to that of the tube was studied experimentally. Both a Newtonian and a viscoelastic suspending fluid were used in order to determine the influence of viscoelasticity. The extra pressure drop owing to the presence of the suspended drops, the shape and velocity of the drops, and the streamlines of the flow are reported for various viscosity ratios, total flow rates and drop sizes.


2016 ◽  
Vol 788 ◽  
Author(s):  
Ehud Yariv ◽  
Itzchak Frankel

When subject to sufficiently strong electric fields, particles and drops suspended in a weakly conducting liquid exhibit spontaneous rotary motion. This so-called Quincke rotation is a fascinating example of nonlinear symmetry-breaking phenomena. To illuminate the rotation of liquid drops we here analyse the asymptotic limit of large electric Reynolds numbers, $\mathit{Re}\gg 1$, within the framework of a two-dimensional Taylor–Melcher electrohydrodynamic model. A non-trivial dominant balance in this singular limit results in both the fluid velocity and surface-charge density scaling as $\mathit{Re}^{-1/2}$. The flow is governed by a self-contained nonlinear boundary-value problem that does not admit a continuous fore–aft symmetric solution, thus necessitating drop rotation. Furthermore, thermodynamic arguments reveal that a fore–aft asymmetric solution exists only when charge relaxation within the suspending liquid is faster than that in the drop. The flow problem possesses both mirror-image (with respect to the direction of the external field) and flow-reversal symmetries; it is transformed into a universal one, independent of the ratios of electric conductivities and dielectric permittivities in the respective drop phase and suspending liquid phase. The rescaled angular velocity is found to depend weakly upon the viscosity ratio. The corresponding numerical solutions of the exact equations indeed collapse at large $\mathit{Re}$ upon the asymptotically calculated universal solution.


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