The dynamics of the cavitation bubble collapse is a fundamental issue for the bubble collapse application and prevention. In the present work, the modified forcing scheme for the pseudopotential multi-relaxation-time ...The dynamics of the cavitation bubble collapse is a fundamental issue for the bubble collapse application and prevention. In the present work, the modified forcing scheme for the pseudopotential multi-relaxation-time lattice Boltzmann model developed by Li Q et al. [ Li Q, Luo K H and Li X J 2013 Phys. Rev. E 87 053301] is adopted to develop a cavitation bubble collapse model. In the respects of coexistence curves and Laplace law verification, the improved pseudopotential multi-relaxation-time lattice Boltzmann model is investigated. It is found that the thermodynamic consistency and surface tension are independent of kinematic viscosity. By homogeneous and heterogeneous cavitation simulation, the ability of the present model to describe the cavitation bubble development as well as the cavitation inception is verified. The bubble collapse between two parallel walls is simulated. The dynamic process of a collapsing bubble is consistent with the results from experiments and simulations by other numerical methods. It is demonstrated that the present pseudopotential multirelaxation-time lattice Boltzmann model is applicable and efficient, and the lattice Boltzmann method is an alternative tool for collapsing bubble modeling.展开更多
An improved unslotted CSMA/CA MAC scheme of HORNET based on the node structure with variable optical buffer is reported. It can be used for transmitting high effectively all variable IP packets in the WDM network.
In a recent paper, an efficient semi-implicit finite element scheme for 2-dimensional tidal flow computations is proposed. In that scheme, each term of the governing equations, rather than each dependent variable, is ...In a recent paper, an efficient semi-implicit finite element scheme for 2-dimensional tidal flow computations is proposed. In that scheme, each term of the governing equations, rather than each dependent variable, is ex- panded in terms of the unknown nodal values. Simpson's rule ix used for numerical integration to make the mass matrix diagonal. The friction terms are represented semi-implicitly to improve stability, but no additional compu- tational effort is required. The shortcomings of this scheme are that the time-stepping scheme is only first-order ae- curate and artificial smoothing is required to control the numerical noise. In this paper, the previous scheme is im- proved by including the eddy viscosity terms in the governing equations to replace artificial smoothing in noise con- trol and the time-stepping scheme is modified to make it second-order accurate. These improvements can be achieved with only a slight increase in computational effort. The test cases used previously to validate the former scheme are again employed to test the present scheme.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11274092 and 1140040119)the Natural Science Foundation of Jiangsu Province,China(Grant No.SBK2014043338)
文摘The dynamics of the cavitation bubble collapse is a fundamental issue for the bubble collapse application and prevention. In the present work, the modified forcing scheme for the pseudopotential multi-relaxation-time lattice Boltzmann model developed by Li Q et al. [ Li Q, Luo K H and Li X J 2013 Phys. Rev. E 87 053301] is adopted to develop a cavitation bubble collapse model. In the respects of coexistence curves and Laplace law verification, the improved pseudopotential multi-relaxation-time lattice Boltzmann model is investigated. It is found that the thermodynamic consistency and surface tension are independent of kinematic viscosity. By homogeneous and heterogeneous cavitation simulation, the ability of the present model to describe the cavitation bubble development as well as the cavitation inception is verified. The bubble collapse between two parallel walls is simulated. The dynamic process of a collapsing bubble is consistent with the results from experiments and simulations by other numerical methods. It is demonstrated that the present pseudopotential multirelaxation-time lattice Boltzmann model is applicable and efficient, and the lattice Boltzmann method is an alternative tool for collapsing bubble modeling.
文摘An improved unslotted CSMA/CA MAC scheme of HORNET based on the node structure with variable optical buffer is reported. It can be used for transmitting high effectively all variable IP packets in the WDM network.
文摘In a recent paper, an efficient semi-implicit finite element scheme for 2-dimensional tidal flow computations is proposed. In that scheme, each term of the governing equations, rather than each dependent variable, is ex- panded in terms of the unknown nodal values. Simpson's rule ix used for numerical integration to make the mass matrix diagonal. The friction terms are represented semi-implicitly to improve stability, but no additional compu- tational effort is required. The shortcomings of this scheme are that the time-stepping scheme is only first-order ae- curate and artificial smoothing is required to control the numerical noise. In this paper, the previous scheme is im- proved by including the eddy viscosity terms in the governing equations to replace artificial smoothing in noise con- trol and the time-stepping scheme is modified to make it second-order accurate. These improvements can be achieved with only a slight increase in computational effort. The test cases used previously to validate the former scheme are again employed to test the present scheme.
