The interaction between strain-rate and rotation in shear flow turbulence from inertial range to dissipative length scales

Direct numerical simulation data from the self similar region of a planar mixing layer is filtered at four different length scales, from the Taylor microscale to the dissipative scales, and is used to examine the scale dependence of the strain-rotation interaction in shear flow turbulence. The interaction is examined by exploring the alignment between the extensive strain-rate eigenvector and the vorticity vector. Results show that the mechanism for enstrophy amplification (propensity of which increases when the two vectors are parallel) is scale dependent with the probability of the two vectors being parallel higher for larger length scales. However, the mechanism for enstrophy attenuation, i.e., the probability of the two vectors being perpendicular to each other, appears to be scale independent.