  SO(3) and SO(2) decompositions of numerical channel flow turbulence are
performed. The decompositions are used to probe, characterize, and quantify
anisotropic structures in the flow. Close to the wall the anisotropic modes are
dominant and reveal the flow structures. The SO(3) decomposition does not
converge for large scales as expected. However, in the shear buffer layer it
also does not converge for small scales, reflecting the lack of small scales
isotropization in that part of the channel flow.
