MICROBUBBLE INJECTION DEVICE FOR REDUCING THE FLUID FRICTIONAL RESISTANCE AGAINST A VESSEL

摘要

A microbubble injection device in the form of a strap (2) which is fixed about the beam of a waterborne vessel (4). The strap (2) has an aerofoil-shaped cross-section and has a duct (3) running through it. The outer wall of the strap (2) is largely foraminous (6); atmospheric air flowing through the duct and out through the pores of the outer wall reduces skin friction in the turbulent boundary layer by injection of microbubbles of air between the vessel and the water.