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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

This study investigates the impact of molecular thermal fluctuations oncompressible decaying isotropic turbulence using the unified stochasticparticle (USP) method, encompassing both two-dimensional (2D) andthree-dimensional (3D) scenarios. The findings reveal that the turbulentspectra of velocity and thermodynamic variables follow the wavenumber scalinglaw of ${k}^{(d-1)}$ for different spatial dimensions $d$ within the highwavenumber range, indicating the impact of thermal fluctuations on small-scaleturbulent statistics. With the application of Helmholtz decomposition, it isfound that the thermal fluctuation spectra of solenoidal and compressiblevelocity components (${\vec{u}}_{s}$ and ${\vec{u}}_{c}$) follow an energyratio of 1:1 for 2D cases, while the ratio changes to 2:1 for 3D cases.Comparisons between 3D turbulent spectra obtained through USP simulations anddirect numerical simulations of the Navier-Stokes equations demonstrate thatthermal fluctuations dominate the spectra at length scales comparable to theKolmogorov length scale. Additionally, the effect of thermal fluctuations onthe spectrum of ${\vec{u}}_{c}$ is significantly influenced by variations inthe turbulent Mach number. We further study the impact of thermal fluctuationson the predictability of turbulence. With initial differences caused by thermalfluctuations, different flow realizations display significant disparities invelocity and thermodynamic fields at larger scales after a certain period oftime, which can be characterized by "inverse error cascades". Moreover, theresults suggest a strong correlation between the predictabilities ofthermodynamic fields and the predictability of ${\vec{u}}_{c}$.

Effect of thermal fluctuations on spectra and predictability in compressible decaying isotropic turbulence