A Slice of Strain-rate —Douglas Carter, University of Southampton

This image is constructed from planar particle image velocimetry data obtained in a zero-mean turbulence box facility (Re_lambda = 250) and processed to a vector resolution equal to 1.5 times the Kolmogorov scale. The projected strain-rate field, calculated as the square of the symmetric part of the reduced velocity gradient tensor, reveals beautiful patterns indicative of small scale turbulence.

https://fluids.ac.uk/files/05_Douglas_Carter_turbulent_strain-rate_zero_mean.1605613933.png