Capillary force and torque on spheroidal particles floating at a fluid interface beyond the superposition approximation

''Inert'' colloids are μm-scale particles that create no distortion when trapped at a planar fluid-fluid interface. When placed in a curved interface, however, such colloids can create interfacial distortions of...

Download Full-text

A generalized examination of capillary force balance at contact line: On rough surfaces or in two-liquid systems

Journal of Colloid and Interface Science ◽

10.1016/j.jcis.2020.11.100 ◽

2021 ◽

Vol 585 ◽

pp. 320-327

Author(s):

JingCun Fan ◽

Joël De Coninck ◽

HengAn Wu ◽

FengChao Wang

Keyword(s):

Contact Line ◽

Capillary Force ◽

Rough Surfaces ◽

Force Balance ◽

Liquid Systems

Download Full-text

Numerical Modeling of the Motion and Interaction of a Droplet of an Inkjet Printing Process with a Flat Surface

Applied Sciences ◽

10.3390/app11020527 ◽

2021 ◽

Vol 11 (2) ◽

pp. 527

Author(s):

Tim Tofan ◽

Harald Kruggel-Emden ◽

Vytautas Turla ◽

Raimondas Jasevičius

Keyword(s):

Level Set ◽

Stokes Equations ◽

Field Method ◽

Phase Field Method ◽

Navier Stokes ◽

Stable Form ◽

Fluid Interface ◽

Velocity Change ◽

Navier Stokes Equations ◽

Inkjet Printhead

The numerical simulation and analysis of the ejection of an ink droplet through a nozzle as well its motion through air until its contact with a surface and taking up of a stable form is performed. The fluid flow is modeled by the incompressible Navier–Stokes equations with added surface tension. The presented model can be solved using either a level set or a phase field method to track the fluid interface. Here, the level set method is used to determinate the interface between ink and air. The presented work concentrates on the demonstration how to check the suitability of ink for inkjet printhead nozzles, for instance, for the use in printers. The results such as velocity, change of size, and volume dependence on time of an ink droplet are presented. Recommendations for the use of specific inks are also given.

Download Full-text

An Investigation of Silica Aerogel to Reduce Acoustic Crosstalk in CMUT Arrays

Sensors ◽

10.3390/s21041459 ◽

2021 ◽

Vol 21 (4) ◽

pp. 1459

Author(s):

Varshitha Yashvanth ◽

Sazzadur Chowdhury

Keyword(s):

Silica Aerogel ◽

Ultrasonic Transducer ◽

Fluid Interface ◽

Fractional Bandwidth ◽

Neighboring Element ◽

Element Analysis ◽

Average Improvement ◽

Capacitive Micromachined Ultrasonic Transducer ◽

Scholte Wave ◽

Fea Simulation

This paper presents a novel technique to reduce acoustic crosstalk in capacitive micromachined ultrasonic transducer (CMUT) arrays. The technique involves fabricating a thin layer of diisocyanate enhanced silica aerogel on the top surface of a CMUT array. The silica aerogel layer introduces a highly nanoporous permeable layer to reduce the intensity of the Scholte wave at the CMUT-fluid interface. 3D finite element analysis (FEA) simulation in COMSOL shows that the developed technique can provide a 31.5% improvement in crosstalk reduction for the first neighboring element in a 7.5 MHz CMUT array. The average improvement of crosstalk level over the −6 dB fractional bandwidth was 22.1%, which is approximately 5 dB lower than that without an aerogel layer. The results are in excellent agreement with published experimental results to validate the efficacy of the new technique.

Download Full-text