The propagation behaviour of an initial thermal perturbation in liquid argon is simulated by the molecular dynamics method.The 12-6 Lennard-Jones potential and mirror boundary conditions are employed in the 32768parti...The propagation behaviour of an initial thermal perturbation in liquid argon is simulated by the molecular dynamics method.The 12-6 Lennard-Jones potential and mirror boundary conditions are employed in the 32768particle three-dimensional simulation.Macroscopic characteristics such as the kinetic temperature,pressure and momentum profiles are monitored during the simulation in order to examine the heat propagation behaviour under a timescale comparable with the relaxation time.The results show that the behaviour is still diffusionlike;no features predicted by the Cattaneo-Vernotte model have been found.The wave-like front of the local temperature may be caused by the adiabatic compression and expansion by the pressure wave generated by the thermal expansion.展开更多
Using time dependent compressible laminar Navier-Stokes equations with a finite volume method incorporating a third-order-accurate discretization scheme, the flow structures around a slender at certain incidences are ...Using time dependent compressible laminar Navier-Stokes equations with a finite volume method incorporating a third-order-accurate discretization scheme, the flow structures around a slender at certain incidences are numerical simulated and typical crossflow patterns are presented. At incidence 10°, these vortical configurations are different at dissimilar axial locations though they are symmetric. At 35°, the symmetric vortical structures still maintain over the slender, yet their interaction at afterbody is intense than that at the forehody since the two vortices have fully developed downstream. The unstable topological structure of trajectory of saddle-to-saddle points and multiple limit cycle are further discussed in topological stability theory. These structures easily produce bifurcation with perturbation. The results support the view of hydrodynamic instability of vortices flow field.展开更多
文摘The propagation behaviour of an initial thermal perturbation in liquid argon is simulated by the molecular dynamics method.The 12-6 Lennard-Jones potential and mirror boundary conditions are employed in the 32768particle three-dimensional simulation.Macroscopic characteristics such as the kinetic temperature,pressure and momentum profiles are monitored during the simulation in order to examine the heat propagation behaviour under a timescale comparable with the relaxation time.The results show that the behaviour is still diffusionlike;no features predicted by the Cattaneo-Vernotte model have been found.The wave-like front of the local temperature may be caused by the adiabatic compression and expansion by the pressure wave generated by the thermal expansion.
文摘Using time dependent compressible laminar Navier-Stokes equations with a finite volume method incorporating a third-order-accurate discretization scheme, the flow structures around a slender at certain incidences are numerical simulated and typical crossflow patterns are presented. At incidence 10°, these vortical configurations are different at dissimilar axial locations though they are symmetric. At 35°, the symmetric vortical structures still maintain over the slender, yet their interaction at afterbody is intense than that at the forehody since the two vortices have fully developed downstream. The unstable topological structure of trajectory of saddle-to-saddle points and multiple limit cycle are further discussed in topological stability theory. These structures easily produce bifurcation with perturbation. The results support the view of hydrodynamic instability of vortices flow field.
