Hydrodynamic Friction Drag Reduction (IMAGE) World Scientific Caption Presented in the figure is percent drag reduction, %DR, as a function of the span-wise gas flux, q, required to obtain Air Layer Drag Reduction (ALDR) on a 13m flat plate in the US Navy's Large Cavitation Channel with a free-stream speed of 11.1 m s-1. The threshold for ALDR was set at 80 percent drag reduction: the dark line in the figure. The different curves represent various downstream measurement positions relative to the injection location. As is evident in the figure, once sufficient air is injected, an air layer is formed with near total friction drag reduction for the length of the plate. Credit Marc Perlin (University of Michigan, USA), Steven Ceccio (University of Michigan, USA) Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.