English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The nonlinear and nonlocal coupling of vorticity and strain-rate constitutesa major hindrance in understanding the self-amplification of velocity gradientsin turbulent fluid flows. Utilizing highly-resolved direct numericalsimulations of isotropic turbulence in periodic domains of up to $12288^3$ gridpoints, and Taylor-scale Reynolds number $R_\lambda$ in the range $140-1300$,we investigate this non-locality by decomposing the strain-rate tensor intolocal and non-local contributions obtained through Biot-Savart integration ofvorticity in a sphere of radius $R$. We find that vorticity is predominantlyamplified by the non-local strain coming beyond a characteristic scale size,which varies as a simple power-law of vorticity magnitude. The underlyingdynamics preferentially align vorticity with the most extensive eigenvector ofnon-local strain. The remaining local strain aligns vorticity with theintermediate eigenvector and does not contribute significantly toamplification; instead it surprisingly attenuates intense vorticity, leading tobreakdown of the observed power-law and ultimately also the scale-invariance ofvorticity amplification, with important implications for prevailingintermittency theories.

Non-local amplification of intense vorticity in turbulent flows