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Transverse structure of turbulence in a rotating gravity current
Author(s) -
Umlauf L.,
Arneborg L.,
Burchard H.,
Fiekas V.,
Lass H. U.,
Mohrholz V.,
Prandke H.
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2007gl029521
Subject(s) - turbulence , physics , gravity current , asymmetry , current (fluid) , dissipation , mechanics , stratification (seeds) , turbulence kinetic energy , boundary layer , entrainment (biomusicology) , kinetic energy , geophysics , computational physics , classical mechanics , internal wave , thermodynamics , seed dormancy , germination , botany , quantum mechanics , dormancy , biology , rhythm , acoustics
Synoptic, high‐resolution, measurements of turbulent kinetic energy dissipation, current velocity and water column stratification across a fast (up to 0.7 m s −1 ) oceanic saline gravity current are presented. Our data provide, for the first time, a detailed two‐dimensional picture of the turbulence structure inside a gravity current. Strong boundary‐layer and interfacial turbulence can be distinguished from a quiet core, and a strong asymmetry of mixing near the outer edges of the gravity current is apparent. This asymmetry is mirrored by the computed entrainment velocities, varying approximately by a factor of 5 across the gravity current. It is argued that the asymmetry is due to rotational effects that can be clearly identified also in the velocity and density fields.