Brunt-Vaisala frequency

Explain the physical meaning of the Brunt-Vaisala frequency. 

In early type stars, the bottom boundary penetrates into convective core (Osaki 1975). Accordingly, convective motion of eddies excites sound waves, as in the case of acoustic noise emmision from incompressible turbulence, shown by Lighthill (1978). Since the frequency of excited waves is higher than the Brunt-Vaisala frequency at the photosphere, the waves are not trapped, but running outward (cf. Unno et al 1979). 

Bundesamt fiir Seeschifffahrt und Hydrographic, Hamburg und Rostock (German Federal Maritime and Hydrographic Agency, Hamburg and Rostock) Brunt Vaisala Frequency... 

Brunt-Vaisala frequency Frequency of vertical oscillation of an air parcel released after displacement from its equilibrium position. 

Now let us turn to yet another oscillatory mode in the liquid layer. Indeed, if the liquid layer is deep enough, and hence stratified there is also the possibility of internal waves of frequency given by the Brunt- Vaisala frequency... 

U, L, H are the characteristic velocity, length and layer thickness scales. L/j is the Rossby deformation radius. The Rossby number measures the importance of rotation on the flow, the Burger number measures the stratification in the atmosphere via the Brunt-Vaisala frequency. As it is known, the atmospheric structure in the giant planets in the solar system is in bands. This structure evolves from shallow-water turbulence. Two dimensional turbulence is characterized by an inverse energy cascade—this means a transfer from small to large scales. 

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