The propagation features, stabilities and dynamical characteristic structures of coupled Kelvin inner modes and second order Rossby inner modes are studied using a simple tropical coupled air-sea model in this paper. ...The propagation features, stabilities and dynamical characteristic structures of coupled Kelvin inner modes and second order Rossby inner modes are studied using a simple tropical coupled air-sea model in this paper. It is shown that there is mechanism of selecting scale and frequency in the tropical air-sea system. The effects of air-sea coupling are mainly on the large-scale modes and nonuniform. These effects make the frequency of Kelvin modes decrease and even excite the eastward propagating Rossby inner modes. These effects make the unstable development of Kelvin modes and result in the decay of Rossby modes. The effects of atmospheric damp are opposite to those of air-sea coup- ling. The oceanic damp only make the wave amplitudes decay. Simutaneously, this paper shows the dynamical character- istic structures of air-sea coupled system and the phase relations between the atmospheric and the oceanic wave compo- nent.展开更多
The Kelvin-Helmholtz instability is believed to be the dominant instability mechanism for free shear flows at large Reynolds numbers. At small Reynolds numbers, a new instability mode is identified when the temporal i...The Kelvin-Helmholtz instability is believed to be the dominant instability mechanism for free shear flows at large Reynolds numbers. At small Reynolds numbers, a new instability mode is identified when the temporal instability of parallel viscous two fluid mixing layers is extended to current-fluid mud systems by considering a composite error function velocity profile. The new mode is caused by the large viscosity difference between the two fluids. This interfacial mode exists when the fluid mud boundary layer is sufficiently thin. Its performance is different from that of the Kelvin-Helmholtz mode. This mode has not yet been reported for interface instability problems with large viscosity contrasts. These results are essential for further stability analysis of flows relevant to the breaking up of this type of interface.展开更多
文摘The propagation features, stabilities and dynamical characteristic structures of coupled Kelvin inner modes and second order Rossby inner modes are studied using a simple tropical coupled air-sea model in this paper. It is shown that there is mechanism of selecting scale and frequency in the tropical air-sea system. The effects of air-sea coupling are mainly on the large-scale modes and nonuniform. These effects make the frequency of Kelvin modes decrease and even excite the eastward propagating Rossby inner modes. These effects make the unstable development of Kelvin modes and result in the decay of Rossby modes. The effects of atmospheric damp are opposite to those of air-sea coup- ling. The oceanic damp only make the wave amplitudes decay. Simutaneously, this paper shows the dynamical character- istic structures of air-sea coupled system and the phase relations between the atmospheric and the oceanic wave compo- nent.
基金supported by the National Natural Science Foundation of China (Grants 11172307, 11232012 11572332)973 Program (Grant 2014CB046200)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant XDB22040203)
文摘The Kelvin-Helmholtz instability is believed to be the dominant instability mechanism for free shear flows at large Reynolds numbers. At small Reynolds numbers, a new instability mode is identified when the temporal instability of parallel viscous two fluid mixing layers is extended to current-fluid mud systems by considering a composite error function velocity profile. The new mode is caused by the large viscosity difference between the two fluids. This interfacial mode exists when the fluid mud boundary layer is sufficiently thin. Its performance is different from that of the Kelvin-Helmholtz mode. This mode has not yet been reported for interface instability problems with large viscosity contrasts. These results are essential for further stability analysis of flows relevant to the breaking up of this type of interface.
