Improvements in or relating to fluid-solid boundary surfaces

摘要

585,865. Reducing surface friction between a solid and a fluid. GRIFFITH, A. A. Aug. 20, 1945, No. 21272. Addition to 578,763. [Class 4] A fluid-solid boundary surface comprising boundary layer suction slots as claimed in the parent Specification is provided a short distance upstream of at least one of the suction slots with 'a further , slot directed towards the suction slot, air being blown through the slot ovet the boundary surface towards the suction slot. The invention is shown applied to an aircraft wing with convex forward surface portions 10 and concave trailing edge portions 12, between which are located the boundary layer suction slots 13, 13a facing upstream, additional slots 16, 16a being provided on the downstream sides of the convex' surfaces 10, and inclined downstreamwardly at an acute angle thereto. The slots 13, 13a communicate with a pump 15 which supplies air at an increased pressure to the slots 16, 16a through conduits 18. Instead of connecting the conduits 18 to the air pump 15, they may communicate with a forwardly facing opening in the loading edge of the wing. The width of the additional slots 16, 16a is approximately equal to, or greater than,. that of the suction slots 13, 13a, and the distance between them is approximately ten times the width of the slots 16, 16a.