An Optimized-Parameter Spectral Clustering Approach to Coherent Structure Detection in Geophysical Flows
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fluids-06-00039.pdf
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Author(s)
Filippi, Margaux
Rypina, Irina I.
Hadjighasem, Alireza
Peacock, Thomas
Date Issued
January 2021
Journal
Fluids
Publisher
MDPI AG
Citation
Fluids 6 (1): 39 (2021)
Version
Final published version
Abstract
In Lagrangian dynamics, the detection of coherent clusters can help understand the organization of transport by identifying regions with coherent trajectory patterns. Many clustering algorithms, however, rely on user-input parameters, requiring a priori knowledge about the flow and making the outcome subjective. Building on the conventional spectral clustering method of Hadjighasem et al. (2016), a new optimized-parameter spectral clustering approach is developed that automatically identifies optimal parameters within pre-defined ranges. A noise-based metric for quantifying the coherence of the resulting coherent clusters is also introduced. The optimized-parameter spectral clustering is applied to two benchmark analytical flows, the Bickley Jet and the asymmetric Duffing oscillator, and to a realistic, numerically generated oceanic coastal flow. In the latter case, the identified model-based clusters are tested using observed trajectories of real drifters. In all examples, our approach succeeded in performing the partition of the domain into coherent clusters with minimal inter-cluster similarity and maximum intra-cluster similarity. For the coastal flow, the resulting coherent clusters are qualitatively similar over the same phase of the tide on different days and even different years, whereas coherent clusters for the opposite tidal phase are qualitatively different.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
Woods Hole Oceanographic Institution
Terms of Use
Creative Commons Attribution
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DOI of Published Version
https://doi.org/10.3390/fluids6010039
