scholarly journals Experimental study on the formation and break-up of fluid bubbles

2020 ◽  
Vol 12 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Oana Daciana BOTTA ◽  
István MAGOS ◽  
Corneliu BALAN
Keyword(s):  
Experimental Study ◽  
Surface Tension ◽  
Vegetable Oil ◽  
High Speed ◽  
Experimental Investigations ◽  
Dynamical Process ◽  
Soap Bubble ◽  
Ohnesorge Number ◽  
Soap Bubbles ◽  
Break Up

The study of fluid surfaces plays an important role in understanding the interfaces encountered in biological systems, as it allows for the investigation of the basic characteristics such as the formation, stability and permeability. Moreover, the adhesion and the fusion of biological membranes can be better understood by the experimental investigations of drops and bubbles formation in controlled dynamical processes. These studies have the potential to generate novel and value information for medical applications in the diagnosis and therapy using microfluidic-based biosensors and controlled drug-delivery micro-devices. In this paper, the dynamics of fluid interfaces have been studied experimentally and a method for determining the surface/interfacial tension is proposed. The analysis started with the investigation of the soap bubble formation and break-up. The rupture was triggered manually, by pinching the tip with a needle. The burst was recorded with high-speed cameras and the burst speed was determined. Furthermore, the thickness of the fluid membrane was approximated and the surface tension was calculated using the Culick-Taylor's law. The obtained values for the surface tension were in the same order of magnitude with that from the literature, thus, considering that the employed method can lead to adequate results. Subsequently, a set-up was created to automatically generate fluid bubbles, at different imposed flow rates. The spontaneous burst was analyzed for three different liquids: soap solution, vegetable oil and polyacrylamide. The phenomenon is characterized by the Ohnesorge number, which takes into account the influence of viscous forces in relation to the inertial and surface tension forces. For the soap bubbles, the obtained thickness of the membrane was in the range of (300-500) nm. The calculated surface tension was found to be 0.038 N/m. In the case of automatically generated fluid bubbles, the lowest Ohnesorge number was obtained for soap bubbles and the highest for oil bubbles. Moreover, soap bubbles had the highest break-up speed, while vegetable oil and polyacrylamide had lower and similar break-up speeds. The experimental study described in this paper is an alternative method for the identification of material parameters, such as density and surface tension, in a dynamical process. Numerical simulations are reported from the viewpoint of servo time constant performance.

Fragmentation of acoustically levitating droplets by laser-induced cavitation bubbles

2016 ◽  
Vol 805 ◽  
pp. 551-576 ◽  
Author(s):  
Silvestre Roberto Gonzalez Avila ◽  
Claus-Dieter Ohl
Keyword(s):  
Shock Wave ◽  
Experimental Study ◽  
Surface Tension ◽  
Cavitation Bubble ◽  
High Speed ◽  
Size Range ◽  
Sound Field ◽  
Negative Pressures ◽  
Impulsive Pressure ◽  
Small Bubbles

We report on an experimental study on the dynamics and fragmentation of water droplets levitated in a sound field exposed to a single laser-induced cavitation bubble. The nucleation of the cavitation bubble leads to a shock wave travelling inside the droplet and reflected from pressure release surfaces. Experiments and simulations study the location of the high negative pressures inside the droplet which result into secondary cavitation. Later, three distinct fragmentation scenarios are observed: rapid atomization, sheet formation and coarse fragmentation. Rapid atomization occurs when the expanding bubble, still at high pressure, ruptures the liquid film separating the bubble from the surrounding air and a shock wave is launched into the surrounding air. Sheet formation occurs due to the momentum transfer of the expanding bubble; for sufficiently small bubbles, the sheet retracts because of surface tension, while larger bubbles may cause the fragmentation of the sheet. Coarse fragmentation is observed after the first collapse of the bubble, where high-speed jets emanate from the surface of the droplet. They are the result of surface instability of the droplet combined with the impulsive pressure generated during collapse. A parameter plot for droplets in the size range between 0.17 and 1.5 mm and laser energies between 0.2 and 4.0 mJ allows the separation of these three regimes.

Soap bubbles seeding for quantitative time resolved velocity measurements of a turbulent wake flow behind a cylinder

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Amine Koched ◽  
Giuseppe Serra ◽  
Giampaolo Romano ◽  
Carsten Kyal ◽  
Jean Stefanini
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Air Flow ◽  
Wake Flow ◽  
Laser Source ◽  
Soap Bubble ◽  
Velocity Measurements ◽  
Time Resolved ◽  
Soap Bubbles ◽  
Open Test

The wake flow behind a cylinder of 100mm diameter is investigated using time resolved 2D PIV technique applied to an air flow generated in a closed loop open test section wind tunnel. The flow is seeded using a micro soap bubble generator (BG-1000, TSI Inc.). The bubbles in the air flow were illuminated with a CW laser source and imaged using a high-speed camera. The main purpose of this study is to show features and advantages of using soap bubbles as seeding for a relatively large-scale PIV investigation under low power illumination conditions.

scholarly journals Numerical and Experimental Investigations on Vocal Fold Approximation in Healthy and Simulated Unilateral Vocal Fold Paralysis

2021 ◽  
Vol 11 (4) ◽  
pp. 1817
Author(s):  
Zheng Li ◽  
Azure Wilson ◽  
Lea Sayce ◽  
Amit Avhad ◽  
Bernard Rousseau ◽  
...  
Keyword(s):  
Computational Model ◽  
Vocal Fold ◽  
High Speed ◽  
Computational Models ◽  
Ex Vivo ◽  
Vocal Fold Paralysis ◽  
Future Application ◽  
Experimental Investigations ◽  
Type I ◽  
Mri Scans

We have developed a novel surgical/computational model for the investigation of unilat-eral vocal fold paralysis (UVFP) which will be used to inform future in silico approaches to improve surgical outcomes in type I thyroplasty. Healthy phonation (HP) was achieved using cricothyroid suture approximation on both sides of the larynx to generate symmetrical vocal fold closure. Following high-speed videoendoscopy (HSV) capture, sutures on the right side of the larynx were removed, partially releasing tension unilaterally and generating asymmetric vocal fold closure characteristic of UVFP (sUVFP condition). HSV revealed symmetric vibration in HP, while in sUVFP the sutured side demonstrated a higher frequency (10–11%). For the computational model, ex vivo magnetic resonance imaging (MRI) scans were captured at three configurations: non-approximated (NA), HP, and sUVFP. A finite-element method (FEM) model was built, in which cartilage displacements from the MRI images were used to prescribe the adduction, and the vocal fold deformation was simulated before the eigenmode calculation. The results showed that the frequency comparison between the two sides was consistent with observations from HSV. This alignment between the surgical and computational models supports the future application of these methods for the investigation of treatment for UVFP.

scholarly journals Physically Based Soap Bubble Synthesis for VR

2021 ◽  
Vol 11 (7) ◽  
pp. 3090
Author(s):  
Sangwook Yoo ◽  
Cheongho Lee ◽  
Seongah Chin
Keyword(s):  
Virtual Reality ◽  
Virtual Space ◽  
Soap Bubble ◽  
Temporal Constraints ◽  
High Expectations ◽  
Soap Bubbles ◽  
Physical Motion ◽  
Head Mounted Display ◽  
Interesting Topic ◽  
Physically Based

To experience a real soap bubble show, materials and tools are required, as are skilled performers who produce the show. However, in a virtual space where spatial and temporal constraints do not exist, bubble art can be performed without real materials and tools to give a sense of immersion. For this, the realistic expression of soap bubbles is an interesting topic for virtual reality (VR). However, the current performance of VR soap bubbles is not satisfying the high expectations of users. Therefore, in this study, we propose a physically based approach for reproducing the shape of the bubble by calculating the measured parameters required for bubble modeling and the physical motion of bubbles. In addition, we applied the change in the flow of the surface of the soap bubble measured in practice to the VR rendering. To improve users’ VR experience, we propose that they should experience a bubble show in a VR HMD (Head Mounted Display) environment.

Experimental study on laminated glass responses of high-speed trains subject to windblown sand particles loading

2021 ◽  
Vol 300 ◽  
pp. 124332
Author(s):  
Gongxun Deng ◽  
Wen Ma ◽  
Yong Peng ◽  
Shiming Wang ◽  
Song Yao ◽  
...  
Keyword(s):  
Experimental Study ◽  
High Speed ◽  
Laminated Glass ◽  
Windblown Sand ◽  
High Speed Trains ◽  
Sand Particles

scholarly journals Experimental study of water droplet break up in water in oil dispersions using an apparatus that produces localized pressure drops

2019 ◽  
Vol 74 ◽  
pp. 1 ◽  
Author(s):  
Fabricio S. Silva ◽  
Ricardo A. Medronho ◽  
Luiz Fernando Barca
Keyword(s):  
Experimental Study ◽  
Droplet Size Distribution ◽  
Energy Dissipation Rate ◽  
Experimental Results ◽  
Good Prediction ◽  
Pressure Drops ◽  
Turbulence Suppression ◽  
Kolmogorov Length Scale ◽  
Control Production ◽  
Break Up

Oil production facilities have choke/control valves to control production and protect downstream equipment against over pressurization. This process is responsible for droplets break up and the formation of emulsions which are difficult to treat. An experimental study of water in oil dispersion droplets break up in localized pressure drop is presented. To accomplish that, an apparatus simulating a gate valve was constructed. Droplet Size Distribution (DSD) was measured by laser light scattering. Oil physical properties were controlled and three different break up models were compared with the experimental results. All experimental maximum diameters (dmax) were above Kolmogorov length scale. The results show that dmax decreases with increase of energy dissipation rate (ε) according to the relation dmax ∝ ε−0.42. The Hinze (1955, AIChE J.1, 3, 289–295) model failed to predict the experimental results, although, it was able to adjust reasonably well those points when the original proportional constant was changed. It was observed that increasing the dispersed phase concentration increases dmax due to turbulence suppression and/or coalescence phenomenon. Turbulent viscous break up model gave fairly good prediction.

Experimental Study of Turbulent Macroinstabilities in an Agitated System with Axial High-Speed Impeller and with Radial Baffles

1996 ◽  
Vol 61 (6) ◽  
pp. 856-867 ◽  
Author(s):  
Oldřich Brůha ◽  
Ivan Fořt ◽  
Pavel Smolka ◽  
Milan Jahoda
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
High Speed ◽  
Experimental Results ◽  
Turbulent Regime ◽  
Frequency Of Occurrence ◽  
Visualization Method ◽  
Entire Flow

The frequency of turbulent macroinstability occurrence was measured in liquids agitated in a cylindrical baffled vessel. As it has been proved by preceding experimental results of the authors, the stochastic quantity with frequency of occurrence of 10-1 to 100 s-1 is concerned. By suitable choosing the viscosity of liquids and frequency of impeller revolutins, the region of Reynolds mixing numbers was covered from the pure laminar up to fully developed turbulent regime. In addition to the equipment making it possible to record automatically the macroinstability occurrence, also the visualization method and videorecording were employed. It enabled us to describe in more detail the form of entire flow field in the agitated system and its behaviour in connection with the macroinstability occurrence. It follows from the experiments made that under turbulent regime of flow of agitated liquids the frequency of turbulent macroinstability occurrence is the same as the frequency of the primary circulation of agitated liquid.

Sign in / Sign up

Export Citation Format

Share Document