Synchronization of low Reynolds number plane Couette turbulence

We demonstrate that in plane Couette turbulence a separation of the velocity field large and small scales according to streamwise Fourier decomposition allows us identify an active subspace comprising number gravest components flow can synchronize all remaining components. The critical wavelength, $\ell _{x c}$ , separates from synchronized passive is identified as wavelength at which perturbations time-dependent turbulent with wavelengths _x<\ell _{xc}$ have negative characteristic Lyapunov exponents. found be approximately 130 wall units obeys viscous scaling these Reynolds numbers.