The growth and collapse of cavitation bubbles near composite surfaces

1989 ◽  
Vol 203 ◽  
pp. 199-214 ◽  
Author(s):  
A. Shima ◽  
Y. Tomita ◽  
D. C. Gibson ◽  
J. R. Blake
Keyword(s):  
Experimental Study ◽  
Bubble Size ◽  
The State ◽  
Bubble Collapse ◽  
Viscoelastic Materials ◽  
Effective Parameters ◽  
Composite Surface ◽  
Surface Stiffness ◽  
Cavitation Bubbles

An experimental study has been made of the growth and collapse of a bubble near a composite surface consisting of two viscoelastic materials. The migratory characteristics of the bubble are examined by means of streak photography. The bubble migration depends not only on the properties of the composite surface but also on bubble size and distance from the surface. Both the surface stiffness and surface inertia are considered to be effective parameters contributing to the bubble migration: the former seeming to be a particularly important factor. The state of neutral bubble collapse, with no migration towards or away from a surface, can be made to occur with an appropriate combination of the surface stiffness and inertia.

scholarly journals Characterizing viscoelastic materials via ensemble-based data assimilation of bubble collapse observations

2021 ◽  
pp. 104455
Author(s):  
Jean-Sebastien Spratt ◽  
Mauro Rodriguez ◽  
Kevin Schmidmayer ◽  
Spencer H. Bryngelson ◽  
Jin Yang ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Bubble Collapse ◽  
Viscoelastic Materials

Hate Speech as an Indicator for the State of the Society

2021 ◽  
pp. 1-13
Author(s):  
Svenja Schäfer ◽  
Michael Sülflow ◽  
Liane Reiners
Keyword(s):  
Experimental Study ◽  
Public Opinion ◽  
Sexual Orientation ◽  
Social Cohesion ◽  
Hate Speech ◽  
Social Groups ◽  
The State ◽  
Controversial Issues ◽  
User Comments ◽  
Research Questions

Abstract. Previous research indicates that user comments serve as exemplars and thus have an effect on perceived public opinion. Moreover, they also shape the attitudes of their readers. However, studies almost exclusively focus on controversial issues if they explore the consequences of user comments for attitudes and perceived public opinion. The current study wants to find out if hate speech attacking social groups due to characteristics such as religion or sexual orientation also has an effect on the way people think about these groups and how they think society perceives them. Moreover, we also investigated the effects of hate speech on prejudiced attitudes. To explore the hypotheses and research questions, we preregistered and conducted a 3 × 2 experimental study varying the amount of hate speech (none/few/many hateful comments) and the group that was attacked (Muslims/homosexuals). Results show no effects of the amount of hate speech on perceived public opinion for both groups. However, if homosexuals are attacked, hate speech negatively affects perceived social cohesion. Moreover, for both groups, we find interaction effects between preexisting attitudes and hate speech for discriminating demands. This indicates that hate speech can increase polarization in society.

Experimental Study of Chamber Volume Effect on Bubble Formation From Orifice Plates Submerged in Water

2018 ◽  
Author(s):  
Omkar S. Gokhale ◽  
Milind A. Jog ◽  
Raj M. Manglik
Keyword(s):  
Experimental Study ◽  
Bubble Size ◽  
Bubble Formation ◽  
Orifice Plate ◽  
Orifice Diameter ◽  
Equilibrium Contact Angle ◽  
Growth Time ◽  
Size And Shape ◽  
Chamber Volume ◽  
Gas Chamber

Experimental study of air bubble formation from orifice plates submerged in water pools has been carried out. Air is forced through the orifice by supplying it to a chamber connected to the orifice plate. The chamber volume plays an important role in determining the bubble growth time as well as bubble size and shape at departure. The effect of chamber volume is generally correlated in term of a dimensionless parameter, capacitance number (Nc), which is proportional to the chamber volume and is inversely proportional to the square of the orifice diameter. To better understand and characterize this effect, an experimental study is performed using ten orifice plates of diameter ranging from 0.61 mm to 2.261 mm with six different chamber volumes between 12 cc and 59 cc with the corresponding capacitance numbers varying from 0.2 to 19. The shape and size of the bubble are captured using high speed videography. The orifice plate material is acrylic glass which has an equilibrium contact angle of 38° with pure water. It was observed that the value of critical capacitance number or Nc above which the bubble evolution is affected by the gas chamber volume, is around 0.85. The bubbles are more spherical in shape, and the growth time is significantly smaller. Also, at high capacitance number (Nc > 7), the air flow in the bubble is so high that the bubble departs with a sharp apex and has a large volume. Above Nc > 10, the chamber effects plateau and further increase in gas chamber volume does not alter bubble size and shape at departure.

scholarly journals A Photographic Study of Spark-Induced Cavitation Bubble Collapse

1972 ◽  
Vol 94 (4) ◽  
pp. 825-832 ◽  
Author(s):  
C. L. Kling ◽  
F. G. Hammitt
Keyword(s):  
Cavitation Bubble ◽  
High Speed ◽  
Bubble Collapse ◽  
Solid Boundary ◽  
High Speed Photography ◽  
Minimum Volume ◽  
Cavitation Bubbles ◽  
Flowing System

The collapse of spark-induced cavitation bubbles in a flowing system was studied by means of high speed photography. The migration of cavitation bubbles toward a nearby solid boundary during collapse and rebound was observed. Near its minimum volume the bubble typically formed a high speed microjet, which struck the nearby surface causing individual damage craters on soft aluminum.

Effective parameters for sand production in unconsolidated formations: An experimental study

2013 ◽  
Vol 105 ◽  
pp. 34-42 ◽  
Author(s):  
P.G. Ranjith ◽  
M.S.A. Perera ◽  
W.K.G. Perera ◽  
B. Wu ◽  
S.K. Choi
Keyword(s):  
Experimental Study ◽  
Effective Parameters ◽  
Sand Production

Experimental study of temperature effect on the growth and collapse of cavitation bubbles near a rigid boundary

2013 ◽  
Vol 9 (4) ◽  
pp. 317-320 ◽  
Author(s):  
Xiu-mei Liu ◽  
Zheng Long ◽  
Jie He ◽  
Bei-bei Li ◽  
Xin-hua Liu ◽  
...  
Keyword(s):  
Experimental Study ◽  
Temperature Effect ◽  
Rigid Boundary ◽  
Cavitation Bubbles
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