A treecode-accelerated vortex method with remeshing and adaptive refinement [1,2] is applied to simulate an elliptic vortex  in an incompressible inviscid fluid using the Lagrangian Biot-Savart formulation. As the vortex evolves, thin filaments develop at the edge of the vortex, and surrounding fluid is entrained forming a tripole structure, while the vortex core and outer bands become axisymmetric. Color figures show the vorticity evolution on logarithmic scale; b/w figures show the adaptive computational grid using a refinement criterion based on local vorticity variation.
 P. Bosler, L. Wang, C. Jablonowski, R. Krasny, Fluid Dynamics Research 46:031406 (2014)
 P. Li, H. Johnston, R. Krasny, J. Comput. Phys. 228:3858-3868 (2009)
 P. Koumoutsakos, J. Comput. Phys. 138:821-857 (1997)