The long-time dynamics of large particles trapped in two nonhomogeneous turbulent shear flows is studied
experimentally. Both flows present a common feature, a shear region that separates two colliding circulations,
but with different spatial symmetries and temporal behaviors. Because large particles are less and less sensitive
to flow fluctuations as their size increases, we observe the emergence of a slow dynamics corresponding to
back-and-forth motions between two attractors, and a super-slow regime synchronized with flow reversals when
they exist. Such dynamics is substantially reproduced by a one-dimensional stochastic model of an overdamped
particle trapped in a two-well potential, forced by a colored noise. An extended model is also proposed that
reproduces observed dynamics and trapping without potential barrier: the key ingredient is the ratio between the
time scales of the noise correlation and the particle dynamics. A total agreement with experiments requires the
introduction of spatially nonhomogeneous fluctuations and a suited confinement strength