Riblets are small streamwise-aligned ridges that are able to reduce skin-friction drag in turbulent flows. When properly shaped, this anisotropic type of surface roughness results in a lower friction drag than the one found on a smooth wall at the same value of Reynolds number Re.

How do riblets reduce drag?

3.1.

Many studies have shown that riblet surfaces only have drag reduction effect in turbulent-flow regime. ... By keeping the vortices above the riblet tips, the cross-stream velocity fluctuations inside the riblet valleys are much lower than the cross-stream velocity fluctuations above a flat plate [33].

What's the difference between ribs and riblets?

Riblets are simply smaller pieces cut from a full rack, while rib tips are meaty chunks from the underside of spare ribs that contain cartilage but no bone. ... Like full ribs, these little morsels benefit from low and slow cooking on the grill or in a smoker.