Effect of homogeneous shear flow on small long-lived perturbations in a stratified fluid
When small perturbations with a rich enough spectral composition decay in anisotropic media, because of the dependence of the decay rate on direction with the passage of time perturbations of certain preferred orientations tend to predominate. In a homogeneous, structurally isotropic fluid anisotropy is induced by shear flow. Thanks to the shear effect in the initial inviscid stage certain perturbations may even be amplified. On the other hand, in a stratified fluid at rest the direction of gravity is preferred and large-scale interval waves and perturbations in the form of horizontal layered structures are the longest-lived. The most slowly decaying perturbations are analyzed for the combination of uniform stratification and homogeneous unbounded horizontal shear flow.
homogeneous, structurally isotropic fluid
scientific article; zbMATH DE number 4087346
scientific article