Year: 2026
Type: article
Abstract: Lagrangian measurements of tracer particle dispersion in stratified turbulence are presented from a large-scale experiment achieving both high buoyancy Reynolds numbers and low Froude numbers-a regime characteristic of oceanic conditions. Stratification has a pronounced effect on the vertical particle dispersion, which is observed to be constrained to distances on the order of the buoyancy scale w_{std}/N, where w_{std} is the standard deviation of the vertical velocity and N is the Brunt-Väisälä frequency. As expected in strongly nonlinear, stratified turbulence, the frequency spectrum of the Lagrangian velocity becomes isotropic at frequencies higher than N. The spectral decay follows a 1/f^{3} scaling, which contrasts with the 1/f^{2} behavior typical of homogeneous isotropic turbulence. At time scales corresponding to internal waves, the statistics of velocity increments remain Gaussian, consistent with the weakly nonlinear regime of wave turbulence. At smaller scales, however, the flow exhibits strongly non-Gaussian statistics, indicative of fully nonlinear turbulent dynamics driven by wave breaking.
Source: Physical Review Letters
DOI: 10.1103/8nm7-pm39
Institutions: Institut polytechnique de Grenoble, Centre National de la Recherche Scientifique, Laboratoire des Écoulements Géophysiques et Industriels, Université Grenoble Alpes, Imperial College London, École Nationale Supérieure de Techniques Avancées, Institut Polytechnique de Paris, École Nationale Supérieure de Techniques Avancées Paris
Language: English
Subfield: Computational Mechanics
Field: Engineering
Domain: Physical Sciences
Open Access status: green
Award: G6671969758
OpenAlex ID: W7163984966