TY - JOUR
T1 - Large-Scale Spectral Structure with a Gap in the Stably Stratified Atmosphere
AU - Chen, T M
AU - Larsen, Søren Ejling
AU - Pécseli, Hans
AU - Mikkelsen, Torben
PY - 1985
Y1 - 1985
N2 - The analysis of the large-scale structure of turbulence in a stratified atmosphere is important for the prediction and modelling of turbulence. The Monin-Obukhov similarity consideration is well suited for the modelling of small-scale turbulence. But the large-scale turbulence possesses new features and parameters, as connected with the appearance of a spectral gap in the stably stratified atmosphere, for the understanding of which an analytical investigation is needed. By a group-kinetic method, we derive the anisotropic form of the transfer function and its governing eddy viscosity. On this basis, we obtain the spectral laws k-5/3, k-1, k-3 for the subranges of inertia, shear, and buoyancy, respectively. A gap connects the last two subranges by the variable anisotropy, as a result of the fall of the spectrum of the vertical velocity fluctuations. The variable anisotropy causes the deviations from the spectral laws k-1 and k-3. Our experiment supports our analytical prediction.
AB - The analysis of the large-scale structure of turbulence in a stratified atmosphere is important for the prediction and modelling of turbulence. The Monin-Obukhov similarity consideration is well suited for the modelling of small-scale turbulence. But the large-scale turbulence possesses new features and parameters, as connected with the appearance of a spectral gap in the stably stratified atmosphere, for the understanding of which an analytical investigation is needed. By a group-kinetic method, we derive the anisotropic form of the transfer function and its governing eddy viscosity. On this basis, we obtain the spectral laws k-5/3, k-1, k-3 for the subranges of inertia, shear, and buoyancy, respectively. A gap connects the last two subranges by the variable anisotropy, as a result of the fall of the spectrum of the vertical velocity fluctuations. The variable anisotropy causes the deviations from the spectral laws k-1 and k-3. Our experiment supports our analytical prediction.
U2 - 10.1088/0031-8949/31/6/026
DO - 10.1088/0031-8949/31/6/026
M3 - Journal article
SN - 0031-8949
VL - 31
SP - 616
EP - 620
JO - Physica Scripta
JF - Physica Scripta
IS - 6
ER -