European drag-reduction research — recent developments and current status

The recent developments and current status of the drag-reduction research in Europe are described here with an overview of European Research Community on Flow, Turbulence and Combustion (ERCOFTAC) where a large amount of research work has been coordinated in the last 10 yr. This is followed by the discussions of some of the recent results on riblets, compliant coating, drag reduction in nature, polymer additives and wall oscillation with an emphasis on the drag-reduction mechanisms involved.