Abstract: A fluid dynamic body having a trailing edge with a pattern formed thereon, the pattern can include a plurality of smoothly surfaced adjacent members with respective interstices therebetween, wherein at least one of the interstices completely contains a porous barrier. In some embodiments, the porous barrier can obstruct fluid flow through the respective interstice between a first surface of the fluid dynamic body on a first side of the trailing edge and a second surface of the fluid dynamic body on a second side of the trailing edge. This helps to reduce noise produced at the trailing edge. In some embodiments, the fluid dynamic body is a wind turbine blade or an air-engine blade.