The Z–S–C multiphase lattice Boltzmann model [Zheng, Shu, and Chew(ZSC), J. Comput. Phys. 218, 353(2006)]is favored due to its good stability, high efficiency, and large density ratio. However, in terms of mass cons...The Z–S–C multiphase lattice Boltzmann model [Zheng, Shu, and Chew(ZSC), J. Comput. Phys. 218, 353(2006)]is favored due to its good stability, high efficiency, and large density ratio. However, in terms of mass conservation, this model is not satisfactory during the simulation computations. In this paper, a mass correction is introduced into the ZSC model to make up the mass leakage, while a high-order difference is used to calculate the gradient of the order parameter to improve the accuracy. To verify the improved model, several three-dimensional multiphase flow simulations are carried out,including a bubble in a stationary flow, the merging of two bubbles, and the bubble rising under buoyancy. The numerical simulations show that the results from the present model are in good agreement with those from previous experiments and simulations. The present model not only retains the good properties of the original ZSC model, but also achieves the mass conservation and higher accuracy.展开更多
随着斜拉桥跨度的增大,斜拉索长度也越来越长,但安装位置存在变相折减,导致阻尼器所能提供的阻尼比降低,这给斜拉索减振阻尼器的设计带来了新的挑战。采用数值方法研究了粘滞惯质阻尼器(Viscous Inertial Mass Damper,VIMD)的斜拉索减...随着斜拉桥跨度的增大,斜拉索长度也越来越长,但安装位置存在变相折减,导致阻尼器所能提供的阻尼比降低,这给斜拉索减振阻尼器的设计带来了新的挑战。采用数值方法研究了粘滞惯质阻尼器(Viscous Inertial Mass Damper,VIMD)的斜拉索减振效果。首先,建立了两端点不处于同一水平高度的斜拉索面内运动微分方程,采用有限差分法对运动方程进行数值求解。然后,以苏通大桥A30号斜拉索为工程背景,对比分析了在惯性质量和阻尼系数这两个参数影响下张紧弦模型和斜拉索模型差异,研究了各参数对三维斜拉索-VIMD系统模态阻尼比的影响。研究结果表明:将联惯质单元并联连入传统粘滞阻尼器,可有效提高斜拉索的模态阻尼比;斜拉索-VIMD系统的动力特性分析可由张紧弦-VIMD系统代替,由于拉索倾角和阻尼器空间位置影响,二者之间存在倍数关系。展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11862003 and 81860635)the Key Project of the Natural Science Foundation of Guangxi Zhuang Autonomous Region,China(Grant No.2017GXNSFDA198038)+3 种基金the Project of Natural Science Foundation of Guangxi Zhuang Autonomous Region,China(Grant No.2018GXNSFAA281302)the Project for Promotion of Young and Middle-aged Teachers’Basic Scientific Research Ability in Guangxi Universities,China(Grant No.2019KY0084)the“Bagui Scholar”Teams for Innovation and Research Project of Guangxi Zhuang Autonomous Region,Chinathe Graduate Innovation Program of Guangxi Normal University,China(Grant No.JXYJSKT-2019-007)。
文摘The Z–S–C multiphase lattice Boltzmann model [Zheng, Shu, and Chew(ZSC), J. Comput. Phys. 218, 353(2006)]is favored due to its good stability, high efficiency, and large density ratio. However, in terms of mass conservation, this model is not satisfactory during the simulation computations. In this paper, a mass correction is introduced into the ZSC model to make up the mass leakage, while a high-order difference is used to calculate the gradient of the order parameter to improve the accuracy. To verify the improved model, several three-dimensional multiphase flow simulations are carried out,including a bubble in a stationary flow, the merging of two bubbles, and the bubble rising under buoyancy. The numerical simulations show that the results from the present model are in good agreement with those from previous experiments and simulations. The present model not only retains the good properties of the original ZSC model, but also achieves the mass conservation and higher accuracy.
文摘随着斜拉桥跨度的增大,斜拉索长度也越来越长,但安装位置存在变相折减,导致阻尼器所能提供的阻尼比降低,这给斜拉索减振阻尼器的设计带来了新的挑战。采用数值方法研究了粘滞惯质阻尼器(Viscous Inertial Mass Damper,VIMD)的斜拉索减振效果。首先,建立了两端点不处于同一水平高度的斜拉索面内运动微分方程,采用有限差分法对运动方程进行数值求解。然后,以苏通大桥A30号斜拉索为工程背景,对比分析了在惯性质量和阻尼系数这两个参数影响下张紧弦模型和斜拉索模型差异,研究了各参数对三维斜拉索-VIMD系统模态阻尼比的影响。研究结果表明:将联惯质单元并联连入传统粘滞阻尼器,可有效提高斜拉索的模态阻尼比;斜拉索-VIMD系统的动力特性分析可由张紧弦-VIMD系统代替,由于拉索倾角和阻尼器空间位置影响,二者之间存在倍数关系。
