Space-Filtering Approach for Localized Dissipative Phenomena in Stratified Turbulent Flows
Abstract
Studying how the energy is transferred through scales in stably stratified turbulent flows with local-in-space tools is necessary to better understand the behavior of geophysical flows, such as the atmosphere and oceans, which are characterized by a strong anisotropy, due to gravity and/or rotation, and inhomogeneity, due to intermittent extreme events and coherent structures. In addition it has been recently observed that, in a narrow range of the Froude number compatible with geophysical frameworks, stratified flows tend to develop large-scale intermittent events in the form of vertical velocity drafts affecting the turbulent dynamics and the energy content of these flows (Feraco et al., EPL, 2018 & 2021). For these reasons the classical paradigm of constant-flux local cascades (in Fourier space) is sometimes not suitable to well capture whether the energy transfer is localized in the configuration space. To characterize how the presence of vertical drafts impacts on the energy transfer, here we apply a space-filtering technique (as in Camporeale, PRL 2018) to several direct numerical simulations of the Boussinesq equations. The most powerful aspect of the space-filtering approach is that it allows an analysis of the cross-scale energy transfer with scale-dependent quantities that are locally defined in the physical space. We observe that, in a specific range of scales likely associated to the emerging drafts, these extreme events locally enhance the transfer of kinetic energy and may represent a mechanism of energy injection for the potential temperature field.
- Feraco et al., 2018, EPL, Vol. 123 (4), p.44002- F. Feraco et al., 2021, EPL, 135 14001- Camporeale et al., 2018, PRL, 120, 125101- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFMNG21B..02F