On the Boeing 787, for the first time, the engine nacelles will have scalloped rear-edge chevrons. The chevrons, developed by the 787 nacelle manufacturer Goodrich as a result of research carried out by Boeing with GE Aviation and Rolls-Royce, will cut down greatly on the noise made by fast-moving air exiting the engine shearing against the external air. This GEnx engine, mounted on GE's 747 test aircraft, clearly shows the nacelle chevrons. Credit: GE Aviation
Clean, Quiet, Powerful: Engines for the New Jets By Chris Kjelgaard