The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Anjie Hu - One of the best experts on this subject based on the ideXlab platform.
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Force method in a pseudo-potential lattice Boltzmann model
Journal of Computational Physics, 2015Co-Authors: Anjie Hu, Longjian Li, Rizwan UddinAbstract:Single component pseudo-potential lattice Boltzmann models have been widely studied due to their simplicity and stability in multiphase simulations. While numerous models have been proposed, comparative analysis and advantages and disadvantages of different force schemes are often lacking. A pseudo-potential model to simulate large density ratios proposed by Kupershtokh et al. 1] is analyzed in detail in this work. Several common used force schemes are utilized and results compared. Based on the numerical results, the relatively most accurate force scheme proposed by Guo et al. 2] is selected and applied to improve the accuracy of Kupershtokh et al.'s model. Results obtained using the modified Kupershtokh et al.'s model 1] for different value of ? are compared with those obtained using Li et al.'s model 3]. Effect of relaxation time ? on the accuracy of the results is reported. Moreover, it is noted that the error in the density ratio predicted by the model is directly correlated with the magnitude of the spurious velocities on (curved) interfaces. Simulation results show that, the accuracy of Kupershtokh et al.'s model can be improved with Guo et al.'s force scheme 2]. However, the errors and ?'s effects are still noticeable when density ratios are large. To improve the accuracy of the pseudo-potential model and to reduce the effects of ?, two possible methods were discussed in the present work. Both, a rescaling of the equation of state and multi-relaxation time, are applied and are shown to improve the prediction of the density ratios.
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Surface Tension Adjustment in a Pseudo-Potential Lattice Boltzmann Model
arXiv: Fluid Dynamics, 2014Co-Authors: Anjie Hu, Longjian Li, Rizwan UddinAbstract:Pseudo-potential lattice Boltzmann models have been widely applied in many multiphase simulations. However, most of these models still suffer from some drawbacks such as spurious velocities and untunable surface tension. In this paper, we aim to discuss the surface tension of a popular pseudo-potential model proposed by Kupershtokh et al., which has attracted much attention due to its simplicity and stability. The influence of a parameter on the surface tension in the model is analyzed. Based on the analysis, we proposed a method to adjust surface tension by changing the parameter in the model. However, the density distribution and the stability of the model also depend on the parameter. To adjust the surface tension independently, the pressure tensor modifying method is introduced and numerically tested. The simulation results show that, by applying the pressure tensor modifying method, the surface tension can be adjusted with little influence on the stability and density distributions.
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On equations of state in pseudo-potential multiphase lattice Boltzmann model with large density ratio
International Journal of Heat and Mass Transfer, 2013Co-Authors: Anjie Hu, Longjian Li, Sixu Chen, Quan Liao, Jianbang ZengAbstract:In this paper, a single-component pseudo-potential model is analyzed by modifying corresponding equation of state. Simulation results show that with the modified vdW equation, this model is capable to simulate the multiphase flow with greater range of density ratio than other existing multiphase models and some drawbacks of pseudo-potential model such as large spurious currents are avoided as well. Besides, the influences of the modified method on surface tension are studied. Also, two other typical equations of state are employed, and the simulation results show that both of them work very well under any characteristic temperature and the greatest density ratio could be up to 10(9). (C) 2013 Elsevier Ltd. All rights reserved.
Rizwan Uddin - One of the best experts on this subject based on the ideXlab platform.
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Force method in a pseudo-potential lattice Boltzmann model
Journal of Computational Physics, 2015Co-Authors: Anjie Hu, Longjian Li, Rizwan UddinAbstract:Single component pseudo-potential lattice Boltzmann models have been widely studied due to their simplicity and stability in multiphase simulations. While numerous models have been proposed, comparative analysis and advantages and disadvantages of different force schemes are often lacking. A pseudo-potential model to simulate large density ratios proposed by Kupershtokh et al. 1] is analyzed in detail in this work. Several common used force schemes are utilized and results compared. Based on the numerical results, the relatively most accurate force scheme proposed by Guo et al. 2] is selected and applied to improve the accuracy of Kupershtokh et al.'s model. Results obtained using the modified Kupershtokh et al.'s model 1] for different value of ? are compared with those obtained using Li et al.'s model 3]. Effect of relaxation time ? on the accuracy of the results is reported. Moreover, it is noted that the error in the density ratio predicted by the model is directly correlated with the magnitude of the spurious velocities on (curved) interfaces. Simulation results show that, the accuracy of Kupershtokh et al.'s model can be improved with Guo et al.'s force scheme 2]. However, the errors and ?'s effects are still noticeable when density ratios are large. To improve the accuracy of the pseudo-potential model and to reduce the effects of ?, two possible methods were discussed in the present work. Both, a rescaling of the equation of state and multi-relaxation time, are applied and are shown to improve the prediction of the density ratios.
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Surface Tension Adjustment in a Pseudo-Potential Lattice Boltzmann Model
arXiv: Fluid Dynamics, 2014Co-Authors: Anjie Hu, Longjian Li, Rizwan UddinAbstract:Pseudo-potential lattice Boltzmann models have been widely applied in many multiphase simulations. However, most of these models still suffer from some drawbacks such as spurious velocities and untunable surface tension. In this paper, we aim to discuss the surface tension of a popular pseudo-potential model proposed by Kupershtokh et al., which has attracted much attention due to its simplicity and stability. The influence of a parameter on the surface tension in the model is analyzed. Based on the analysis, we proposed a method to adjust surface tension by changing the parameter in the model. However, the density distribution and the stability of the model also depend on the parameter. To adjust the surface tension independently, the pressure tensor modifying method is introduced and numerically tested. The simulation results show that, by applying the pressure tensor modifying method, the surface tension can be adjusted with little influence on the stability and density distributions.
L. You - One of the best experts on this subject based on the ideXlab platform.
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Calibrating dipolar interaction in an atomic condensate
Physical Review Letters, 2004Co-Authors: S. Yi, L. YouAbstract:dipole-dipole interaction, pseudo potential, shape resonances
Orlando Ayala - One of the best experts on this subject based on the ideXlab platform.
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Towards a thermodynamically consistent pseudo-potential lattice Boltzmann model for multi-component, multiphase miscible mixtures
arXiv: Computational Physics, 2019Co-Authors: Cheng Peng, Luis F. Ayala, Orlando AyalaAbstract:Current multi-component, multiphase pseudo-potential lattice Boltzmann models have thermodynamic inconsistencies that prevent them to correctly predict the phase behaviors of miscible multi-component mixtures, such as hydrocarbon mixtures. This paper identifies these inconsistencies and attempts to design a thermodynamically consistent multi-component, multiphase pseudo-potential lattice Boltzmann model that allows mass transfer across the phase interfaces and is capable to predict the phase behavior of typically miscible hydrocarbon mixtures. The designed model qualitatively predicts the phase behavior of hydrocarbon mixtures, and shows that achieving precise thermodynamic consistency requires enforcing the more general iso-fugacity rule, which is also briefly discussed.
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Isotropy and spurious currents in pseudo-potential multiphase lattice Boltzmann models
Computers & Fluids, 2019Co-Authors: Cheng Peng, Luis F. Ayala, Orlando Ayala, Lian-ping WangAbstract:Abstract The spurious currents observed in multiphase flow simulations with pseudo-potential lattice Boltzmann (LB) models are usually understood to be the result of the lack of isotropy of the model-generated interaction force between phases. Remedies have been proposed to utilize larger stencils to compute the interaction force with higher orders of isotropy. In this short communication, we point out the incompleteness in the current understanding and propose a new consistent implementation to more effectively suppress the spurious currents. We also demonstrate theoretically that certain low-level spurious currents cannot be eliminated by increasing isotropy if the local hydrostatic balance inside the diffuse interface is not established in the LB models.
Cheng Peng - One of the best experts on this subject based on the ideXlab platform.
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Towards a thermodynamically consistent pseudo-potential lattice Boltzmann model for multi-component, multiphase miscible mixtures
arXiv: Computational Physics, 2019Co-Authors: Cheng Peng, Luis F. Ayala, Orlando AyalaAbstract:Current multi-component, multiphase pseudo-potential lattice Boltzmann models have thermodynamic inconsistencies that prevent them to correctly predict the phase behaviors of miscible multi-component mixtures, such as hydrocarbon mixtures. This paper identifies these inconsistencies and attempts to design a thermodynamically consistent multi-component, multiphase pseudo-potential lattice Boltzmann model that allows mass transfer across the phase interfaces and is capable to predict the phase behavior of typically miscible hydrocarbon mixtures. The designed model qualitatively predicts the phase behavior of hydrocarbon mixtures, and shows that achieving precise thermodynamic consistency requires enforcing the more general iso-fugacity rule, which is also briefly discussed.
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Isotropy and spurious currents in pseudo-potential multiphase lattice Boltzmann models
Computers & Fluids, 2019Co-Authors: Cheng Peng, Luis F. Ayala, Orlando Ayala, Lian-ping WangAbstract:Abstract The spurious currents observed in multiphase flow simulations with pseudo-potential lattice Boltzmann (LB) models are usually understood to be the result of the lack of isotropy of the model-generated interaction force between phases. Remedies have been proposed to utilize larger stencils to compute the interaction force with higher orders of isotropy. In this short communication, we point out the incompleteness in the current understanding and propose a new consistent implementation to more effectively suppress the spurious currents. We also demonstrate theoretically that certain low-level spurious currents cannot be eliminated by increasing isotropy if the local hydrostatic balance inside the diffuse interface is not established in the LB models.
