It is shown that for a particle with suitable angular momenta in the screened Coulomb potential or isotropic harmonic potential, there still exist closed orbits rather than ellipse, characterized by the conserved aphe...It is shown that for a particle with suitable angular momenta in the screened Coulomb potential or isotropic harmonic potential, there still exist closed orbits rather than ellipse, characterized by the conserved aphelion and perihelion vectors, i.e. extended Runge-Lenz vector, which implies a higher dynamical symmetry than the geometrical symmetry O_(3). The closeness of a planar orbit implies the radial and angular motional frequencies are commensurable.展开更多
3-D evolution of Karman vortex filaments and vortex filaments in braid regions in the turbulent wake of a 2-D circulax cylinder is investigated numeri- cally based on inviscid vortex dynamics by analyzing the response...3-D evolution of Karman vortex filaments and vortex filaments in braid regions in the turbulent wake of a 2-D circulax cylinder is investigated numeri- cally based on inviscid vortex dynamics by analyzing the response of the initially 2-D spanwise vortex filaments to periodic spanwise disturbance of varying magnitude, wavelength and initial phase angles. Our results reveal a kind of 3-D vortex system in the wake which consists of large scale horseshoe-shaped vortices and small scale λ-shaped vortex filaments as well as vortex loops. The mechanism and the dynamic process about the generation of streamwise vortical structure and the 3-D coherent structure are reported.展开更多
基金the National Natural Science Foundation of China under Grant No.19675002Nonlinear Science Project of China,Post-Doctoral FoundationDoctoral Program Foundation of Education Committee of China.
文摘It is shown that for a particle with suitable angular momenta in the screened Coulomb potential or isotropic harmonic potential, there still exist closed orbits rather than ellipse, characterized by the conserved aphelion and perihelion vectors, i.e. extended Runge-Lenz vector, which implies a higher dynamical symmetry than the geometrical symmetry O_(3). The closeness of a planar orbit implies the radial and angular motional frequencies are commensurable.
文摘3-D evolution of Karman vortex filaments and vortex filaments in braid regions in the turbulent wake of a 2-D circulax cylinder is investigated numeri- cally based on inviscid vortex dynamics by analyzing the response of the initially 2-D spanwise vortex filaments to periodic spanwise disturbance of varying magnitude, wavelength and initial phase angles. Our results reveal a kind of 3-D vortex system in the wake which consists of large scale horseshoe-shaped vortices and small scale λ-shaped vortex filaments as well as vortex loops. The mechanism and the dynamic process about the generation of streamwise vortical structure and the 3-D coherent structure are reported.
