Abstract
We introduce a numerical renormalization group procedure which permits long-time simulations of vortex dynamics and coalescence in a two-dimensional turbulent decaying fluid. The number of vortices decreases as with instead of the value predicted by a naïve kinetic theory. For short time, we find an effective exponent consistent with previous simulations and experiments. We show that the mean square displacement of surviving vortices grows as Introducing effective dynamics for two- and three-body collisions, we justify that only the latter become relevant at a small vortex area coverage. A kinetic theory consistent with this mechanism leads to We find that the theoretical relations between kinetic parameters are all in good agreement with experiments.
- Received 14 December 1999
DOI:https://doi.org/10.1103/PhysRevE.61.6644
©2000 American Physical Society