Experiments were conducted to investigate the dynamics of an oscillating bubble generated by a spark in the presence of an inclined attached air bubble.The study primarily focused on the influence of the inclination a...Experiments were conducted to investigate the dynamics of an oscillating bubble generated by a spark in the presence of an inclined attached air bubble.The study primarily focused on the influence of the inclination angle on the behavior of bubble jetting orientation,air bubble shape modes,and motion characteristics of the interaction between the two bubbles.Various complex bubble jetting behaviors were observed,including the presence of multiple types of bubble jetting directions,bubble splitting,and multidirectional jets.Four types of air bubble shapes were defined,namely inclined cup cover-shaped(with and without splitting),double-peaked cup cover-shaped,and inclined L-shaped air bubbles.The formation of different types of bubble jets was analyzed using the vector synthesis principle of the Bjerknes force exerted by the inclined attached air bubble and a steel plate.To describe the diverse orientations of bubble jetting and air bubble shapes,new parameters namely the dimensionless spark bubble oscillation time T^(*)and volume ratio V^(*)that consider the inclination angle are proposed.The findings of this investigation contribute to the existing knowledge and have the potential to further enhance methods for mitigating cavitation damage in marine,hydraulic machinery systems,and medical fields.l fields.展开更多
Experiments on two cavitation bubbles,which are generated at the same instant,with three different sizes near solid wall are conducted and their impulses on the boundary are registered by polyvinylidene fluoride(PVDF)...Experiments on two cavitation bubbles,which are generated at the same instant,with three different sizes near solid wall are conducted and their impulses on the boundary are registered by polyvinylidene fluoride(PVDF)sensor.Due to being near the boundary,bubble interactions and deformed features are in contrast with those in infinite fluid medium.In this paper,five morphologies of bubble deformation during growth and collapse phases are observed by high-speed camera.These profiles are strongly influenced by inter-bubble distance(η),stand-off distance from boundary(γ),and bubble size differences.Analysis of photographs coupled with sensor measurements enabled qualitative investigation of two bubble interactions on the boundary.From sensor data acquisition,it is confirmed that lower bigger bubble with upper smaller bubble configuration produces highest impulses on the boundary compared with other vertical arrangements of the tandem cavitation bubble employed in this study.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52171311,52271279)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(Grant No.20KJB510046)。
文摘Experiments were conducted to investigate the dynamics of an oscillating bubble generated by a spark in the presence of an inclined attached air bubble.The study primarily focused on the influence of the inclination angle on the behavior of bubble jetting orientation,air bubble shape modes,and motion characteristics of the interaction between the two bubbles.Various complex bubble jetting behaviors were observed,including the presence of multiple types of bubble jetting directions,bubble splitting,and multidirectional jets.Four types of air bubble shapes were defined,namely inclined cup cover-shaped(with and without splitting),double-peaked cup cover-shaped,and inclined L-shaped air bubbles.The formation of different types of bubble jets was analyzed using the vector synthesis principle of the Bjerknes force exerted by the inclined attached air bubble and a steel plate.To describe the diverse orientations of bubble jetting and air bubble shapes,new parameters namely the dimensionless spark bubble oscillation time T^(*)and volume ratio V^(*)that consider the inclination angle are proposed.The findings of this investigation contribute to the existing knowledge and have the potential to further enhance methods for mitigating cavitation damage in marine,hydraulic machinery systems,and medical fields.l fields.
基金The author acknowledges the encouragement that Prof.Hyung Taek Ahn of the Adv Comp Eng Lab in University of Ulsan has given continuously to this research.
文摘Experiments on two cavitation bubbles,which are generated at the same instant,with three different sizes near solid wall are conducted and their impulses on the boundary are registered by polyvinylidene fluoride(PVDF)sensor.Due to being near the boundary,bubble interactions and deformed features are in contrast with those in infinite fluid medium.In this paper,five morphologies of bubble deformation during growth and collapse phases are observed by high-speed camera.These profiles are strongly influenced by inter-bubble distance(η),stand-off distance from boundary(γ),and bubble size differences.Analysis of photographs coupled with sensor measurements enabled qualitative investigation of two bubble interactions on the boundary.From sensor data acquisition,it is confirmed that lower bigger bubble with upper smaller bubble configuration produces highest impulses on the boundary compared with other vertical arrangements of the tandem cavitation bubble employed in this study.
