Trajectory encounter volume as a diagnostic of mixing potential in fluid flows
MetadataShow full item record
Fluid parcels can exchange water properties when coming into contact with each other, leading to mixing. The trajectory encounter mass and a related simplified quantity, the encounter volume, are introduced as a measure of the mixing potential of a flow. The encounter volume quantifies the volume of fluid that passes close to a reference trajectory over a finite time interval. Regions characterized by a low encounter volume, such as the cores of coherent eddies, have a low mixing potential, whereas turbulent or chaotic regions characterized by a large encounter volume have a high mixing potential. The encounter volume diagnostic is used to characterize the mixing potential in three flows of increasing complexity: the Duffing oscillator, the Bickley jet and the altimetry-based velocity in the Gulf Stream extension region. An additional example is presented in which the encounter volume is combined with the u approach of Pratt et al. (2016) to characterize the mixing potential for a specific tracer distribution in the Bickley jet flow. Analytical relationships are derived that connect the encounter volume to the shear and strain rates for linear shear and linear strain flows, respectively. It is shown that in both flows the encounter volume is proportional to time.
© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nonlinear Processes in Geophysics 24 (2017): 189-202, doi:10.5194/npg-24-189-2017.
Suggested CitationNonlinear Processes in Geophysics 24 (2017): 189-202
The following license files are associated with this item:
Showing items related by title, author, creator and subject.
Smith, Keston W.; Aretxabaleta, Alfredo L. (Copernicus Publications on behalf of the European Geosciences Union and the American Geophysical Union, 2007-02-01)Expectation maximization (EM) is used to estimate the parameters of a Gaussian Mixture Model for spatial time series data. The method is presented as an alternative and complement to Empirical Orthogonal Function (EOF) ...
Helfrich, Karl R.; White, Brian L. (Copernicus Publications on behalf of the European Geosciences Union and the American Geophysical Union, 2010-07-15)Large-amplitude internal solitary waves in continuously stratified systems can be found by solution of the Dubreil-Jacotin-Long (DJL) equation. For finite ambient density gradients at the surface (bottom) for waves of ...
Ostrovsky, Lev A.; Helfrich, Karl R. (Copernicus Publications on behalf of the European Geosciences Union and the American Geophysical Union, 2011-02-14)Strongly nonlinear internal waves in a layer with arbitrary stratification are considered in the hydrostatic approximation. It is shown that "simple waves" having a variable vertical structure can emerge from a wide class ...