We trace the Doppler velocity and turbulent velocity elds at diierent heights in the solar overshoot layers using absorption lines of diierent strengths in spec-trograms taken at the center of the solar disk. We show the results for one regular and one exploding granule as two representative examples. The convec-tive velocity patterns do not change with the height up to 200km above 5000 = 1, ne...

The spatiotemporal behavior of the interaction between turbulence and flows has been studied close to the L-H transition threshold conditions in the edge region (ρ≥0.7) of TJ-II plasmas. The temporal dynamics of the interaction displays an oscillatory behavior with a characteristic predator-prey relationship. The spatial evolution of this turbulence-flow oscillation pattern has been measured, s...

[1] Estuarine near‐surface turbulence is important for transport, mixing, and air‐water exchanges of many important constituents but has rarely been studied in detail. Here, we analyze a unique set of estuarine observations of in situ atmospheric and full water column measurements, estimated air‐sea exchanges, and acoustic measurements of several terms in the turbulent kinetic energy (TKE) budg...

The first consistent model for the turbulent tachocline is presented, with the turbulent diffusivity computed within the model instead of being specified arbitrarily. For the origin of the 3D turbulence a new mechanism is proposed. Owing to the strongly stable stratification, the mean radial shear is stable, while the horizontal shear is expected to drive predominantly horizontal, quasi-2D moti...

of turbulence models for shear ows by a double expansion technique," Phys. Fluids \Conservation laws and two ux spectra of hydro-dynamic convective turbulence," Physica D 57 (1992). 15 Bolgiano and Kolmogorov scaling are believed to occur together in general ows; this suggests that the general dissipation rate model could combine the results for both scalings as in Eq. (40). 2 However, a comple...

Previous studies have shown that the isoplanatic distortion due to turbulence and the image of a remote object may be jointly estimated from the 4D mutual intensity across an aperture. This Letter shows that decompressive inference on a 2D slice of the 4D mutual intensity, as measured by a rotational shear interferometer, is sufficient for estimation of sparse objects imaged through turbulence....

Generalized action invariants are identified for various models of drift wave turbulence in the presence of the mean shear flow. It is shown that the wave kinetic equation describing the interaction of the small scale turbulence and large scale shear flow can be naturally writen in terms of these invariants. Unlike the wave energy, which is conserved as a sum of small-and large-scale components...

The effect of momentum injection on the temperature gradient in tokamak plasmas is studied. A plausible scenario for transitions to reduced transport regimes is proposed. The transition happens when there is sufficient momentum input so that the velocity shear can suppress or reduce the turbulence. However, it is possible to drive too much velocity shear and rekindle the turbulent transport. Th...

We present the complete unfolding of streamwise localisation in a paradigm of extended shear flows, namely, two-dimensional plane-Poiseuille flow. Exact solutions of the Navier-Stokes equations are computed numerically and tracked in the streamwise wavenumber Reynolds number parameter space to identify and describe the fundamental mechanism behind streamwise localisation, a ubiquitous feature o...

growth and structure of homogeneous turbulent shear ow," J. \The analysis and model-ing of dilatational terms in compressible turbulence," J.