A general formulation of the variable-elliptic-vortex method for the i
ncompressible Euler equations is derived, and its consistency, stabili
ty and convergence are proved. The main feature of this method is that
not only the centers of the vortex blobs are transported by the induc
ed velocity field, but also the blobs themselves are rotated and defor
med in the elliptic shape according to the Jacobian matrix of the indu
ced velocity field. The variable-elliptic-vortex method provides a mor
e flexible and more reasonable approach to mimic physical Bows and all
ows a smooth transition from vortex blobs to sheets and vice versa. Th
e theoretic analysis indicates that the discretization error using var
iable blobs is smaller than that using fixed blobs. Several issues on
the practical aspects of the method are also addressed.