Dr. Fabio Feraco (IAP) will deliver a talk on the topic, "Vertical drafts in stratified turbulence and their link to small-scale intermittency" at the IAP colloquium.
In his talk he will discuss about the Vertical wind drafts and temperature bursts that are routinely observed in geophysical flows.
These extreme events affect the statistics at large scales and investigating them is essential to improve our understanding of the complex dynamics of such flows.
To the aim of characterizing this phenomenon, his work group performed several direct numerical simulations of the Boussinesq equations, varying the Froude number Fr, the governing parameter of stratification.
They investigate the flows by means of high-order statistics and find that these extreme large-scale events develop only in a sharp range of Fr (~ 0.07 - 0.1) of geophysical interest. 
In the presentation he will show that the emergence of these events in stratified flows can be captured and interpreted thanks to a 1D model derived from the Boussinesq equations. Mixing efficiency and small-scale intermittency trends with Fr are analyzed and linked to the presence of such extreme events in the flow. In particular, they find that small-scale intermittency is enhanced by the presence of the large-scale vertical drafts. Finally, a mechanism for the generation of these events and on their role in the enhancement of vorticity and dissipation in stratified flows will be presented.