Abstract

Turbulence is found in many natural and technical flows. The presentation discusses the major properties of turbulent flows and their mathematical description with focus on the friction drag generated due to turbulent motions. Different attempts to control this drag increase compared to laminar flows are discussed including passive, active and reactive control scenarios. While most of these control techniques aim at tackling small scale structures in turbulence, a recently proposed turbulence scenario includes the presence of so-called turbulent superstructures. Those large-scale structures, which might open up the possibility to alternative control approaches, are actively investigated in the turbulence community at present.