Turbulence comes in bursts in stably stratified flows

Abstract

There is a clear distinction between simple laminar and complex turbulent fluids. But in some cases, as for the nocturnal planetary boundary layer, a stable and well-ordered flow can develop intense and sporadic bursts of turbulent activity which disappear slowly in time. This phenomenon is ill-understood and poorly modeled; and yet, it is central to our understanding of weather and climate dynamics. We present here a simple model which shows that in stably stratified turbulence, the stronger bursts can occur when the flow is expected to be more stable. The bursts are generated by a rapid non-linear amplification of energy stored in waves, and are associated with energetic interchanges between vertical velocity and temperature (or density) fluctuations. Direct numerical simulations on grids of 2048^3 points confirm this somewhat paradoxical result of measurably stronger events for more stable flows, displayed not only in the temperature and vertical velocity derivatives, but also in the amplitude of the fields themselves.

References in corpus (2)

• Velocity Statistics Distinguish Quantum Turbulence from Classical Turbulence
• Geophysical turbulence and the duality of the energy flow across scales

Cited by in corpus (21)

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• Evidence for Bolgiano-Obukhov scaling in rotating stratified turbulence using high-resolution direct numerical simulations
• Large-scale anisotropy in stably stratified rotating flows
• Dual constant-flux energy cascades to both large scales and small scales
• Turbulent density and pressure fluctuations in the stratified intracluster medium
• Waves and vortices in the inverse cascade regime of stratified turbulence with or without rotation
• Scaling laws for mixing and dissipation in unforced rotating stratified turbulence
• Interplay of waves and eddies in rotating stratified turbulence and the link with kinetic-potential energy partition
• Dimensional transition of energy cascades in stably stratified thin fluid layers
• Inverse cascades and resonant triads in rotating and stratified turbulence
• Single-particle Lagrangian statistics from direct numerical simulations of rotating-stratified turbulence
• Exploiting self-organized criticality in strongly stratified turbulence
• Temperature statistics above a deep-ocean sloping boundary
• Single-particle dispersion in stably stratified turbulence
• Phase transition to turbulence via moving fronts
• Understanding the effect of Prandtl number on momentum and scalar mixing rates in neutral and stably stratified flows using gradient field dynamics
• Vertical dispersion of Lagrangian tracers in fully developed stably stratified turbulence
• Automated identification and characterization method of turbulent bursting from single-point records of the velocity field
• Lagrangian irreversibility and energy exchanges in rotating-stratified turbulent flows
• Connecting Large-Scale Velocity and Temperature Bursts with Small-Scale Intermittency in Stratified Turbulence
• Low-dimensional representation of intermittent geophysical turbulence with High-Order Statistics-informed Neural Networks (H-SiNN)