构造迭代函数系统(iterated function system,IFS)仿射变换的相似函数,并在所建立的IFS模糊相似图中搜索带约束条件的最佳路径最大化IFS模糊集隶属函数,从而确定2个IFS特征对应关系.通过插值实现二维IFS分形吸引子变形.实验结果表明:所...构造迭代函数系统(iterated function system,IFS)仿射变换的相似函数,并在所建立的IFS模糊相似图中搜索带约束条件的最佳路径最大化IFS模糊集隶属函数,从而确定2个IFS特征对应关系.通过插值实现二维IFS分形吸引子变形.实验结果表明:所给出的自适应模糊对应算法简单有效,为分形变形技术提供了一种新的处理方法.展开更多
应用广义胞映射图论方法(GCMD)研究了在谐和激励与随机噪声共同作用下的Duffing-Van der Pol 系统的随机分岔现象．系统参数选择在多个吸引子与混沌鞍共存的范围内．研究发现,随着随机激励强度的增大,该系统存在两种分岔现象:一种为随...应用广义胞映射图论方法(GCMD)研究了在谐和激励与随机噪声共同作用下的Duffing-Van der Pol 系统的随机分岔现象．系统参数选择在多个吸引子与混沌鞍共存的范围内．研究发现,随着随机激励强度的增大,该系统存在两种分岔现象:一种为随机吸引子与吸引域边界上的鞍碰撞,此时随机吸引子突然消失;另一种为随机吸引子与吸引域内部的鞍碰撞,此时随机吸引子突然增大．研究证实,当随机激励强度达到某一临界值时,该系统还会发生D-分岔(基于Lyapunov指数符号的改变而定义),此类分岔点不同于上述基于系统拓扑性质改变所得的分岔点．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
文摘构造迭代函数系统(iterated function system,IFS)仿射变换的相似函数,并在所建立的IFS模糊相似图中搜索带约束条件的最佳路径最大化IFS模糊集隶属函数,从而确定2个IFS特征对应关系.通过插值实现二维IFS分形吸引子变形.实验结果表明:所给出的自适应模糊对应算法简单有效,为分形变形技术提供了一种新的处理方法.
文摘应用广义胞映射图论方法(GCMD)研究了在谐和激励与随机噪声共同作用下的Duffing-Van der Pol 系统的随机分岔现象．系统参数选择在多个吸引子与混沌鞍共存的范围内．研究发现,随着随机激励强度的增大,该系统存在两种分岔现象:一种为随机吸引子与吸引域边界上的鞍碰撞,此时随机吸引子突然消失;另一种为随机吸引子与吸引域内部的鞍碰撞,此时随机吸引子突然增大．研究证实,当随机激励强度达到某一临界值时,该系统还会发生D-分岔(基于Lyapunov指数符号的改变而定义),此类分岔点不同于上述基于系统拓扑性质改变所得的分岔点．
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.
