The crossflow instability of a three-dimensional boundary layer is a main factor affecting the transition around the swept-wing.The three-dimensional boundary layer flow affected by the saturated crossflow vortex is v...The crossflow instability of a three-dimensional boundary layer is a main factor affecting the transition around the swept-wing.The three-dimensional boundary layer flow affected by the saturated crossflow vortex is very sensitive to the high frequency disturbances,which foreshadows that the swept wing flow transition will happen.The primary instability of the compressible flow over a swept wing is investigated with nonlinear parabolized stability equations (NPSE).The Floquet theory is then applied to the analysis of the influence of localized steady suction on the secondary instability of crossflow vortex.The results show that suction can significantly suppress the growth of the crossflow mode as well as the secondary instability modes.展开更多
The characteristics of continental shelf waves forced by nonlinear continental shelf topography are studied with a shallowwater model.Results show that there are two topographic Rossby waves and two inertia gravity wa...The characteristics of continental shelf waves forced by nonlinear continental shelf topography are studied with a shallowwater model.Results show that there are two topographic Rossby waves and two inertia gravity waves.The northward propagating topographic Rossby wave couples with the inertia gravity wave into an unstable wave in the long wave band.When the continental slope is increased,the topographic Rossby wave still couples with the inertia gravity wave into an unstable wave,but the frequency decreases.In the South China Sea(SCS),the western boundary can develop an unstable wave because of topographic forcing,nonlinear conditions,and increasing amplitude.It is possible that the unstable wave develops into a vortex.In observations,the SCS has a strong western boundary current and abundant mesoscale vortice.There is a strong relationship between the emergence,disappearance,and movement of the circulation's multi-eddy structure and the seasonal evolvement of the SCS's circulation.This article shows a possible mechanism for the formation of vortices in the SCS.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 90505005 and 10932005)
文摘The crossflow instability of a three-dimensional boundary layer is a main factor affecting the transition around the swept-wing.The three-dimensional boundary layer flow affected by the saturated crossflow vortex is very sensitive to the high frequency disturbances,which foreshadows that the swept wing flow transition will happen.The primary instability of the compressible flow over a swept wing is investigated with nonlinear parabolized stability equations (NPSE).The Floquet theory is then applied to the analysis of the influence of localized steady suction on the secondary instability of crossflow vortex.The results show that suction can significantly suppress the growth of the crossflow mode as well as the secondary instability modes.
基金supported by National Natural Science Foundation of China(Grant Nos.40906014 and 40976015)Science Foundation for Youth of the State Oceanic Administration of China (Grant No. 2010218)
文摘The characteristics of continental shelf waves forced by nonlinear continental shelf topography are studied with a shallowwater model.Results show that there are two topographic Rossby waves and two inertia gravity waves.The northward propagating topographic Rossby wave couples with the inertia gravity wave into an unstable wave in the long wave band.When the continental slope is increased,the topographic Rossby wave still couples with the inertia gravity wave into an unstable wave,but the frequency decreases.In the South China Sea(SCS),the western boundary can develop an unstable wave because of topographic forcing,nonlinear conditions,and increasing amplitude.It is possible that the unstable wave develops into a vortex.In observations,the SCS has a strong western boundary current and abundant mesoscale vortice.There is a strong relationship between the emergence,disappearance,and movement of the circulation's multi-eddy structure and the seasonal evolvement of the SCS's circulation.This article shows a possible mechanism for the formation of vortices in the SCS.
