Summary

Experimental & theoretical observation of unstable coherent structures embedded in transitional turbulence in wall-bounded shear flows give us dynamical insights in the nature of this type of turbulence.

New perspectives:

  1. Computation of dynamical averages and transport properties - turbulent drag, velocity correlations, ... - predictions are exact, obtained by periodic orbit theory.

  2. Nonlinear control. A detailed geometry of the invariant solutions and their unstable manifolds: body forcing or boundary forcing algorithms can chaperon the turbulent fluid toward a desired state.