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Investigation of cavitation bubble collapse near rigid boundary by lattice Boltzmann method

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Journal of Hydrodynamics 2016年第3期28卷 442-450页

作者：单鸣雷朱昌平周曦殷澄韩庆邦 College of Internet of Things Engineering and Jiangsu Key Laboratory of Power Transmission and Distribution Equipment Technology Hohai University

The dynamics of the bubble collapse near a rigid boundary is a fundamental issue for the bubble collapse application and prevention. In this paper, the bubble collapse is modeled by adopting the lattice Boltzmann method （LBM） and is verified, and then the dynamic characteristics of the collapsing bubble with the second collapse is investigated. The widely used Shan-Chen model in the LBM multiphase community is modified by coupling with the Carnahan-Starling equation of state （C-S EOS） and the exact difference method （EDM） for the forcing term treatment. The simulation results of the bubble profile evolution by the LBM are in excellent agreements with the theoretical and experimental results. From the two-dimensional pressure field evolution, the dynamic characteristics of the different parts during the bubble collapse stage are studied. The role of the second collapse in the rigid boundary damage is discussed, and the impeding effect between two collapses is demonstrated.

关键词： cavitation mechanics lattice Boltzmarm method bubble collapse rigid boundary

On study of non-spherical bubble collapse near a rigid boundary

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Journal of Hydrodynamics 2020年第3期32卷 523-535页

作者： Xiao-jian Ma Xin Zhao Biao Huang Xiao-ying Fu Guo-yu Wang School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China Department of Mechanics School of Aerospace EngineeringBeijing Institute of TechnologyBeijing100081China State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu 610065China

This paper applies numerical methods to investigate the non-spherical bubble collapse near a rigid boundary. A three-dimensional model, with the mass conservation equation reformulated for considering the compressibility effect, is built to deal with the coupling between the pressure and the flow velocity in the momentum and energy equations and to simulate the temporal evolution of the single bubble oscillation and its surrounding flow structure. The investigations focus on the global bubble patterns and its schlieren contours, as well as the high-speed jet accompanied when the bubble collapses and the counter jet is generated in the rebound stage. The results show that the robust pressure waves emitted due to the bubble collapse lead to substantial changes of the flow structures around the bubble, especially the formation of the counter jet generated in the rebound stage. Furthermore, compared with the high-speed jet when the bubble collapses, the counter jet in the rebound stage emits the momentum several times greater in the magnitude and in diametrically opposite direction at the monitoring point.

关键词： Bubble jet rigid boundary numerical simulation volume of fluid(VOF) pressure wave

INTERACTION OF A CAVITATION BUBBLE AND AN AIR BUBBLE WITH A rigid boundary

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Journal of Hydrodynamics 2010年第4期22卷 503-512页

作者： XU Wei-lin BAI Li-xin ZHANG Fa-xing State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Chengdu 610065 China Institute of Acoustics Chinese Academy of Sciences Beijing 100190 China

The motion of a spark-induced cavitation bubble and an air bubble near a rigid boundary is experimentally studied by using high-speed *** dimensionless parameters are used to describe the geometrical configuration of the bubble-bubble-boundary *** bubble-bubble interaction can be considered in two different *** cavitation bubble will collapse towards the air bubble if the air bubble is relatively small,and away from the air bubble if the air bubble is relatively *** two zones are identified in the bubble-boundary interaction,and they are the danger zone and the safety *** relative position,the bubble-boundary distance and the bubble-bubble distance play important roles in the bubble-bubble-boundary interaction,which can be considered in several conditions according to the responses of the *** jets are found to penetrate into the cavitation *** cavitation bubble and the air bubble（air jet） move in their own way without *** motion of a cavitation bubble may be influenced by an air bubble and/or a rigid *** influence of the air bubble and the influence of the boundary may be combined,like some thing of a vector.

关键词： cavitation bubble air bubble rigid boundary collapse

Effect of rigid boundary on propagation of torsional surface waves inporous elastic layer

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Applied Mathematics and Mechanics(English Edition) 2011年第3期32卷 327-338页

作者： S. GUPTA A. CHATTOPADHYAY D. K. MAJHI Department of Applied Mathematics Indian School of Mines

The paper presents the effect of a rigid boundary on the propagation of torsional surface waves in a porous elastic layer over a porous elastic half-space using the mechanics of the medium derived by Cowin and Nunziato （Cowin, S. C. and Nunziato, J. W. Linear elastic materials with voids. Journal of Elasticity, 13（2）, 125-147 （1983））. The velocity equation is derived, and the results are discussed. It is observed that there may be two torsional surface wave fronts in the medium whereas three wave fronts of torsional surface waves in the absence of the rigid boundary plane given by Dey et al. （Dey, S., Gupta, S., Gupta, A. K., Kar, S. K., and De, P. K. Propagation of torsional surface waves in an elastic layer with void pores over an elastic half-space with void pores. Tamkang Journal of Science and Engineering, 6（4）, 241-249 （2003））. The results also reveal that in the porous layer, the Love wave is also available along with the torsional surface waves. It is remarkable that the phase speed of the Love wave in a porous layer with a rigid surface is different from that in a porous layer with a free surface. The torsional waves are observed to be dispersive in nature, and the velocity decreases as the oscillation frequency increases.

关键词： torsional surface wave Love wave rigid boundary porous wave front

INFLUENCE OF rigid boundary ON THE LOVE WAVE PROPAGATION IN ELASTIC LAYER WITH VOID PORES

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Acta Mechanica Solida Sinica 2013年第5期26卷 551-558页

作者： Sumit Kumar Vishwakarma Shishir Gupta Dinesh Kumar Majhi Department of Applied Mathematics Indian School of Mines Department of Mathematics Birla Institute of Technology and Science

In this paper, a mathematical model for Love wave propagation in a porous elastic layer under a rigid boundary resting over a poro-elastic half-space has been developed. The study shows that such a medium transmits two types of Love waves. The first front depends on the change in volume fraction of the pores whereas the second front depends upon the modulus of rigidity of the elastic matrix of the medium and is the same as the Love wave in an elastic layer over an elastic half-space. It is observed that the first front is many times faster than the shear wave in the medium with void pores due to the change in the volume fraction of the pores and is significant.

关键词： Love waves void pores volume fraction rigid boundary wave front

Estimation of bedload discharge in sewer pipes with different boundary conditions using an evolutionary algorithm

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International Journal of Sediment Research 2017年第4期32卷 564-574页

作者： Kiyoumars Roushangar Roghayeh Ghasempour Department of Civil Engineering The University of Tabriz

Sediment transport is a complex phenomenon due to the nonlinearity and uncertainties of the *** present study applies Gene Expression Programming（GEP） to develop bedload transport models in sewer pipes. In this regard, two types of bedload were considered: loose bed（deposition state） and rigid bed（limit of deposition state）. In order to develop the models, two scenarios with different input combinations were considered: Scenario 1 considers only hydraulic characteristics and Scenario 2 considers both hydraulic and sediment characteristics as inputs for modeling bedload discharge. The results proved the capability of GEP in prediction of sediment transport and it was found that for prediction of bedload transport in sewer pipes Scenario 2 performed more successfully than Scenario 1. According to the outcome of sensitivity analysis, Frm（Modified Froude number） and d50/y（relative particle size） for rigid boundary and Frmfor loose boundary had key roles in the modeling. The outcome of the GEP models also was compared with existing empirical equations and it was found the GEP models yielded better results. It was also found that pipe diameter affected the transport capacity of the sewer pipe. Increasing pipe diameter caused an increase in model efficiency. A pipe with a diameter of 305 mm yielded to the best results.

关键词： Sediment transport Loose boundary rigid boundary Genetic expression programming Empirical equation