The financial and environmental cost of turbulence is staggering: manage to quell turbulence in the thin boundary layers on the surface of a commercial airliner and you could almost halve the total aerodynamic drag, dramatically cutting fuel burn, emissions and cost of operation. Yet systems-level tools to model scale interactions or control turbulence remain relatively under-developed. Resolvent analysis for turbulent flow provides a simple, but rigorous, approach by which to deconstruct the full turbulence field into a linear combination of modes which interact through the nonlinear term. In this talk, resolvent analysis is used to explore the influence of passive and active control techniques on turbulence structure. Model results obtained using desktop computing power are compared with direct numerical simulation and complex experiments, highlighting the utility of resolvent analysis as a design tool for schemes to control wall turbulence, and the dramatic reduction in complexity associated with sparsity and low-rank behavior in the resolvent. We close with a brief discussion of the potential to exploit these findings to create turbulence with specified, or “designer” properties.

The support of the U.S. Air Force Office of Scientific Research under grant FA 9550-16-1-0361 and the U.S. Office of Naval Research under grant N00014-17-1-2307 is gratefully acknowledged.