Finite time correlations of the velocity in a surface flow are found to be important for the formation of clusters of Lagrangian tracers. The degree of clustering characterized by the Lyapunov spectrum of the flow is numerically shown to be in qualitative agreement with the predictions for the white-in-time compressible Kraichnan flow, but to deviate quantitatively. For intermediate values of compressibility the clustering is surprisingly weakened by time correlations.
Physical Review Letters
- Pub Date:
- September 2004
- Fluctuation phenomena random processes noise and Brownian motion;
- Chaotic Dynamics;
- Fluid Dynamics
- 4 pages, 5 figures, to be published in PRL