Air lubrication: Only big bubbles do the trick
Sunday, September 4, 2016 - 14:21
in Physics & Chemistry
Blowing bubbles underneath a ship’s hull, causes them to be pushed against the surface. In the surface layer between the ship and water, these air bubbles cause less friction: it’s also known as air lubrication. In practice, friction can be reduced 20 percent, with a huge impact on fuel consumption and carbon dioxide emission. The precise mechanism is still unknown, as the local water flow is complex and turbulent. As scientists demonstrate, the size of the bubbles make a big difference: tiny bubble don’t have a net effect at all. This may seem counterintuitive, but large bubbles that can be deformed easily, give the strongest effect.