研究了 Van der Pol- Duffing振子在窄带随机噪声激励下的响应问题。用参数变换法使方程出现小参数 ,用多尺度法分离了系统的快变项 ,讨论了系统的阻尼项、非线性项和随机项等参数对系统的影响。理论分析表明 ,当随机激励强度或带宽增...研究了 Van der Pol- Duffing振子在窄带随机噪声激励下的响应问题。用参数变换法使方程出现小参数 ,用多尺度法分离了系统的快变项 ,讨论了系统的阻尼项、非线性项和随机项等参数对系统的影响。理论分析表明 ,当随机激励强度或带宽增大时系统的响应可从一个极限环变为一扩散的极限环 ;在一定的条件下系统可有两个稳定的稳态解。展开更多
研究了 Van der Pol-Duffing振子在简谐与随机噪声联合激励下的响应问题。用参数变换法使方程出现小参数 ,用多尺度法分离系统的快变项 ,讨论系统的阻尼项、非线性项和随机项等参数对系统响应的影响。理论分析和数值模拟表明 ,当随机激...研究了 Van der Pol-Duffing振子在简谐与随机噪声联合激励下的响应问题。用参数变换法使方程出现小参数 ,用多尺度法分离系统的快变项 ,讨论系统的阻尼项、非线性项和随机项等参数对系统响应的影响。理论分析和数值模拟表明 ,当随机激励强度增大时 ,系统的响应可从一个极限环变为一个扩散的极限环 ;在一定的条件下 ,系统可有两个稳定的稳态解及随机跳跃现象。展开更多
The LBGK(lattice Bhatnagar-Gross-Krook)model of the lattice Boltzmann method including second-order boundary condition treatment for curve geometry was employed to investigate the flow around particle clusters.The dra...The LBGK(lattice Bhatnagar-Gross-Krook)model of the lattice Boltzmann method including second-order boundary condition treatment for curve geometry was employed to investigate the flow around particle clusters.The drag coefficient is a benchmark problem in the analysis of particle-fluid complex systems,especially,in a gas-solid fluidized bed.In the present work,the drag coefficient on a spherical particle in a cluster,was evaluated by using the momentum-exchange method directly.Two different configurations of cluster were measured based on the lattice Boltzmann method.Computational results indicated that the drag coefficient on an individual particle in a cluster depended heavily on the configuration of cluster.And the drag coefficient on the particle in the cluster was lower when that particle was shielded by other particles.Additionally,except for the configuration factor,both the inter-distance and Reynolds number had a strong effect on the drag coefficient on an individual particle as well.It was found that the drag coefficient on each particle varied drastically with clustering.Omitting the effect of clustering might result in incorrect drag forces in the simulation.展开更多
文摘研究了 Van der Pol- Duffing振子在窄带随机噪声激励下的响应问题。用参数变换法使方程出现小参数 ,用多尺度法分离了系统的快变项 ,讨论了系统的阻尼项、非线性项和随机项等参数对系统的影响。理论分析表明 ,当随机激励强度或带宽增大时系统的响应可从一个极限环变为一扩散的极限环 ;在一定的条件下系统可有两个稳定的稳态解。
文摘研究了 Van der Pol-Duffing振子在简谐与随机噪声联合激励下的响应问题。用参数变换法使方程出现小参数 ,用多尺度法分离系统的快变项 ,讨论系统的阻尼项、非线性项和随机项等参数对系统响应的影响。理论分析和数值模拟表明 ,当随机激励强度增大时 ,系统的响应可从一个极限环变为一个扩散的极限环 ;在一定的条件下 ,系统可有两个稳定的稳态解及随机跳跃现象。
文摘The LBGK(lattice Bhatnagar-Gross-Krook)model of the lattice Boltzmann method including second-order boundary condition treatment for curve geometry was employed to investigate the flow around particle clusters.The drag coefficient is a benchmark problem in the analysis of particle-fluid complex systems,especially,in a gas-solid fluidized bed.In the present work,the drag coefficient on a spherical particle in a cluster,was evaluated by using the momentum-exchange method directly.Two different configurations of cluster were measured based on the lattice Boltzmann method.Computational results indicated that the drag coefficient on an individual particle in a cluster depended heavily on the configuration of cluster.And the drag coefficient on the particle in the cluster was lower when that particle was shielded by other particles.Additionally,except for the configuration factor,both the inter-distance and Reynolds number had a strong effect on the drag coefficient on an individual particle as well.It was found that the drag coefficient on each particle varied drastically with clustering.Omitting the effect of clustering might result in incorrect drag forces in the simulation.
