scholarly journals Exploring droplet impact near a millimetre-sized hole: comparing a closed pit with an open-ended pore

2015 ◽  
Vol 772 ◽  
pp. 427-444 ◽  
Author(s):  
Rianne de Jong ◽  
Oscar R. Enríquez ◽  
Devaraj van der Meer
Keyword(s):  
Impact Velocity ◽  
Crucial Role ◽  
Drop Impact ◽  
Impact Dynamics ◽  
Air Bubbles ◽  
Air Bubble ◽  
Impact Location ◽  
Impact Phenomena ◽  
The Impact

We investigate drop impact dynamics near closed pits and open-ended pores experimentally. The resulting impact phenomena differ greatly in each case. For a pit, we observe three distinct phenomena, which we denote as a splash, a jet and an air bubble, whose appearance depends on the distance between impact location and pit. Furthermore, we found that splash velocities can reach up to seven times the impact velocity. Drop impact near a pore, however, results solely in splashing. Interestingly, two distinct and disconnected splashing regimes occur, with a region of planar spreading in between. For pores, splashes are less pronounced than in the pit case. We state that, for the pit case, the presence of air inside it plays the crucial role of promoting splashing and allowing for air bubbles to appear.

Irregular Bubble Entrainment Following Drop Impact on a Free Surface

2003 ◽  
Author(s):  
Yukio Tomita ◽  
Toshiyasu Kasai ◽  
Shinya Miura
Keyword(s):  
Free Surface ◽  
Impact Velocity ◽  
Water Surface ◽  
Drop Impact ◽  
Drop Diameter ◽  
Air Bubbles ◽  
Air Bubble ◽  
Bubble Entrainment ◽  
Irregular Case ◽  
The Impact

An air bubble is entrained by the impact of a drop on a water surface. Consequently sound is emitted. There are two categories of the bubble entrainment depending on the drop diameter dD and impact velocity Vimp. One is the regular entrainment where air bubbles are always pinched off, another is the irregular case where bubbles are trapped irregularly. In this paper we explore the mechanism of the irregular bubble entrainment and induced bubble sound.

Surface breakup and air bubble formation by drop impact in the irregular entrainment region

2007 ◽  
Vol 588 ◽  
pp. 131-152 ◽  
Author(s):  
Y. TOMITA ◽  
T. SAITO ◽  
S. GANBARA
Keyword(s):  
Froude Number ◽  
Water Column ◽  
Water Surface ◽  
Bubble Formation ◽  
Drop Impact ◽  
Air Bubbles ◽  
Bubble Generation ◽  
Air Bubble ◽  
Bubble Entrainment ◽  
The Impact

Drop impact on a water surface can be followed by underwater sounds originating not at the drop impact but when the entrained bubbles oscillate. Although the sound mechanism in the regular bubble entrainment region is well-known, there is less knowledge on the impact phenomena in the irregular bubble entrainment region where various situations can exist, such as many types of bubble formation or even no bubble generation under some conditions. In the present study, the aim is to clarify the dynamics of the water surface after the impact of a primary drop, mainly with diameter 5.2, 5.7 and 6.2mm, each of which is accompanied by a single satellite drop. Special attention was paid to the breakup behaviour of the water surface for Froude number Fr < 300. It was found that three underwater sounds were generated for a single drop impact, besides the sound due to impact itself. The first two were audible to the human ear, but the third one was almost inaudible. The first underwater sound resulted from the oscillation of a single air bubble formed as a result of the satellite drop impact on the bottom of the contracting cavity, and the second sound was due to the oscillation of air bubbles generated during the collapse of the water column. The formation of these air bubbles strongly depends on the Froude number, Weber number (or Bond number) and the aspect ratio of the drop at impact, although involving probability characteristics. Furthermore it is suggested that an air bubble entrapped in a water column plays an important role in increasing the probability of contact between the column surface and the curved free surface. A Japanese Suikinkutsu was introduced as an application of drop-impact-induced sounds. Using an open-type Suikinkutsu an additional experiment was carried out with larger drops with average diameters of 6.2, 7.2 and 7.8, mm.

scholarly journals The role of drop shape in impact and splash

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Qingzhe Liu ◽  
Jack Hau Yung Lo ◽  
Ye Li ◽  
Yuan Liu ◽  
Jinyu Zhao ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Spherical Geometry ◽  
Impact Dynamics ◽  
Helmholtz Instability ◽  
Liquid Drops ◽  
Drop Shape ◽  
Spreading Dynamics ◽  
Solid Substrates ◽  
The Impact

AbstractThe impact and splash of liquid drops on solid substrates are ubiquitous in many important fields. However, previous studies have mainly focused on spherical drops while the non-spherical situations, such as raindrops, charged drops, oscillating drops, and drops affected by electromagnetic field, remain largely unexplored. Using ferrofluid, we realize various drop shapes and illustrate the fundamental role of shape in impact and splash. Experiments show that different drop shapes produce large variations in spreading dynamics, splash onset, and splash amount. However, underlying all these variations we discover universal mechanisms across various drop shapes: the impact dynamics is governed by the superellipse model, the splash onset is triggered by the Kelvin-Helmholtz instability, and the amount of splash is determined by the energy dissipation before liquid taking off. Our study generalizes the drop impact research beyond the spherical geometry, and reveals the potential of using drop shape to control impact and splash.

scholarly journals Lifting a sessile oil drop from a superamphiphobic surface with an impacting one

2020 ◽  
Vol 6 (34) ◽  
pp. eaba4330
Author(s):  
Olinka Ramírez-Soto ◽  
Vatsal Sanjay ◽  
Detlef Lohse ◽  
Jonathan T. Pham ◽  
Doris Vollmer
Keyword(s):  
Surface Tension ◽  
Energy Transfer ◽  
Impact Velocity ◽  
Sessile Drop ◽  
Cloud Formation ◽  
Impact Dynamics ◽  
Combustion Engines ◽  
Intrinsic Properties ◽  
Natural Processes ◽  
The Impact

Colliding drops are encountered in everyday technologies and natural processes, from combustion engines and commodity sprays to raindrops and cloud formation. The outcome of a collision depends on many factors, including the impact velocity and the degree of alignment, and intrinsic properties like surface tension. Yet, little is known on binary impact dynamics of low-surface-tension drops on a low-wetting surface. We investigate the dynamics of an oil drop impacting an identical sessile drop sitting on a superamphiphobic surface. We observe five rebound scenarios, four of which do not involve coalescence. We describe two previously unexplored cases for sessile drop liftoff, resulting from drop-on-drop impact. Numerical simulations quantitatively reproduce the rebound scenarios and enable quantification of velocity profiles, energy transfer, and viscous dissipation. Our results illustrate how varying the offset from head-on alignment and the impact velocity results in controllable rebound dynamics for oil drop collisions on superamphiphobic surfaces.

scholarly journals Maternal or Paternal Diabetes and Its Crucial Role in Offspring Birth Weight and MODY Diagnosis

Metabolites ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 387
Author(s):  
Valeria Calcaterra ◽  
Angela Zanfardino ◽  
Gian Vincenzo Zuccotti ◽  
Dario Iafusco
Keyword(s):  
Birth Weight ◽  
Crucial Role ◽  
Autosomal Dominant ◽  
Maternal Diabetes ◽  
Fetal Weight ◽  
Maturity Onset Diabetes ◽  
Heterogenous Group ◽  
History Of ◽  
The Impact

Maturity-onset diabetes of the young (MODY) represents a heterogenous group of monogenic autosomal dominant diseases, which accounts for 1–2% of all diabetes cases. Pregnancy represents a crucial time to diagnose MODY forms due to the 50% risk of inheritance in offspring of affected subjects and the potential implications on adequate fetal weight. Not only a history of maternal diabetes may affect the birth weight of offspring, paternal diabetes should also be taken into consideration for a correct pathogenetic diagnosis. The crucial role of maternal and paternal diabetes inheritance patterns and the impact of this inherited mutation on birthweight and the MODY diagnosis was discussed.

Numerical Simulation Study on the Wave Dissipating Performance of Air Bubbles Breakwater with Double Air Discharged Pipes

2014 ◽  
Vol 501-504 ◽  
pp. 2112-2115
Author(s):  
Cheng Xing Zhang
Keyword(s):  
Numerical Simulation ◽  
Simulation Study ◽  
Numerical Models ◽  
Variable Density ◽  
Air Bubbles ◽  
Two Phase ◽  
Air Bubble ◽  
The Impact ◽  
Phase Fluid

The numerical simulation of air bubbles breakwater was presented in this paper. The two-phase fluid of water and air was assumed as a variable density fluid. The numerical models were developed by FLUENT in order to explore the air amount scale in the system of air bubbles breakwater . The impact of double air discharged pipes on the wave dissipating performance of air bubble breakwater was obtained, which illuminated that under the condition of equal total air amount of Qp, the wave dissipating performance of air bubbles breakwater with double air discharged pipes breakwater may not be improved in comparison with the air bubbles breakwater with single air discharged pipe.

scholarly journals The Morphology of Ice and Liquid Brine in the Environmental SEM: A Study of the Freezing Methods

2019 ◽  
Author(s):  
Ľubica Vetráková ◽  
Vilém Neděla ◽  
Jiří Runštuk ◽  
Dominik Heger
Keyword(s):  
Time Lapse ◽  
Solute Concentration ◽  
Environmental Scanning ◽  
Air Bubbles ◽  
Ice Recrystallization ◽  
Naturally Occurring ◽  
Polycrystalline Ice ◽  
Entrapped Air ◽  
The Impact

Abstract. The microstructure of polycrystalline ice with a threading solution of brine controls its numerous characteristics, including the ice mechanical properties, ice-atmosphere interactions, sea-ice albedo, and (photo)chemical behavior in/on the ice. Ice samples were previously prepared in laboratories to study various facets of ice-impurities interactions and (photo)reactions to model natural ice-impurities behavior. We examine the impact of the freezing conditions and solute (CsCl used as a proxy for naturally occurring salts) concentrations on the microscopic structure of ice samples via an environmental scanning electron microscope. The method allows us to observe in detail the ice surfaces, namely, the free ice, brine puddles, brine-containing grain boundary grooves, individual ice crystals, and imprints left by entrapped air bubbles at temperatures higher than −25 °C. The amount of brine on the external surface is found proportional to the solute concentration and is strongly dependent on the sample preparation method. Time-lapse images in the condition of slight sublimation reveal sub-surface association of air bubbles with brine. With rising temperature (up to −14 °C), the brine surface coverage increases to remain enhanced during the subsequent cooling and until the final crystallization below the eutectic temperature. The ice recrystallization dynamics identifies the role of surface spikes in retarding the ice boundaries propagation (Zeener pining). The findings thus quantify the amounts of brine exposed to incoming radiation, available for the gas exchange, and influencing other mechanical and optical properties of ice. The results have straightforward implications for artificially prepared and naturally occurring salty ices.

Autonomic countertransference: the psychopathic mind and the institution

2020 ◽  
Vol 2 (2) ◽  
pp. 101-112
Author(s):  
Rob Hale
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Crucial Role ◽  
Therapeutic Process ◽  
Psychopathic Personality ◽  
Personality Structure ◽  
Institutional Level ◽  
Definition Of ◽  
The Impact

This article examines the crucial role of countertransference in the diagnosis and treatment of those with a psychopathic personality structure. The disturbing emotions aroused in the therapist are evoked via the autonomic nervous system. Violence provokes a sympathetic reaction, perverse sexuality a parasympathetic response; in each case this is at largely unconscious level and thus all the more powerful. The impact on the therapeutic process is then examined both at an individual and an institutional level. My definition of a psychopath is "someone who brings out the worst in me".

A fine tuning of embryo loading technique by eliminating the air bubble in the outer sheath of embryo catheter among women undergoing IVF treatment

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jasdev Singh Harbhajan Singh ◽  
Mohd Faizal Ahmad ◽  
Muhammad Azrai Abu ◽  
Mohd Hashim Omar ◽  
Abdul Kadir Abdul Karim
Keyword(s):  
Negative Impact ◽  
Implantation Rate ◽  
Oocyte Retrieval ◽  
Fine Tuning ◽  
Air Bubbles ◽  
Air Bubble ◽  
Beta Hcg ◽  
Group A ◽  
Group B

Abstract Objectives The role of air bubbles in bracketing the embryo-containing medium in inner catheter during embryo transfer (ET) has already been established. However, the role of air bubbles in outer catheter (OC) during implantation is yet to be determined. This study aimed to compare the implantation rates between women who have undergone ET with or without ASP (Vitrolife®; Sweden), a medium use for oocyte retrieval and rinsing in OC embryo catheter. The purpose of introducing the ASP medium to the OC was to eliminate air bubbles in that space during implantation. Methods A total of 312 women were randomly divided into two groups with 156 participants each group. In Group A, ASP medium was used during ET, whereas in Group B, no ASP medium was utilized. Positive implantation was defined as serum beta-hCG level >5 mIU/mL taken on the 7th day following ET. Results The average age of the majority of the participants was 30–39 years and had at least 4–5 years of subfertility. The unexplained subfertility was the prominent cause of ET failure in both groups. In most of the participants in both groups, ET was done using fresh embryo cycles with good to excellent embryo grades. After the ASP medium was manipulated in the OC in both groups, the positive implantation rate was not different in both groups (p>0.05). Conclusions The elimination of air bubbles in OC by using the ASP medium during ET did not confer an additional benefit nor exert a negative impact on implantation rate.

Numerical Simulation Study on the Submerged Pipe Depth of Air Bubbles Breakwater

2013 ◽  
Vol 353-356 ◽  
pp. 2732-2735
Author(s):  
Cheng Xing Zhang
Keyword(s):  
Numerical Simulation ◽  
Simulation Study ◽  
Incident Wave ◽  
Numerical Models ◽  
Variable Density ◽  
Air Bubbles ◽  
Two Phase ◽  
Air Bubble ◽  
The Impact ◽  
Phase Fluid

The numerical simulation of air bubbles breakwater was presented in this paper. The two-phase fluid of water and air was assumed as a variable density fluid. The numerical models were developed by FLUENT in order to explore the air amount scale in the system of air bubbles breakwater . The impact of submerged pipe depth on the wave dissipating performance of air bubble breakwater was obtained, which illuminated that The submerged pipe depth D is deeper, the wave dissipating performance of air bubbles breakwater is better. Furthermore, the effect of air amount and the incident wave periods on the performance of the air bubbles breakwater was analyzed.

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