  The vortices that appear repeatedly and suggest turbulent dynamics are
crucial to the understanding of sheared turbulence. These vortices produce
order out of chaos, benefiting the turbulence modelling that focuses only on
statistically stable quantities. In three dimensions, the hairpin vortices [J.
Zhou, R. Adrian, S. Balachandar, T. Kendall, J. Fluid Mech., 387, 353 (1999);
R. Adrian, Phys. Fluids, 19, 041301 (2007)] play such a fundamental role in the
transport of momentum and energy for wall bounded sheared turbulence. In two
dimensions where the atmospheric flow has a great play, the fundamental
vortices have yet to be observed. Here we report the experimental finding of
the slanted vortices in the quasi-two-dimensional sheared soap-film turbulence.
We also demonstrate how these slanted fundamental vortices, which result from
the interaction between the sheared mean flow and the random turbulent
vortices, could possibly connect to the turbulent transport. The finding here
might introduce another means of understanding the planetary turbulence where
the mean flow is commonly existent and nonuniform.
