Fish scale the surface, interacting only with the riblet tips, not causing any high-veloctiy flow in the valleys. Since this high velocity flow now only interacts with the riblet-tip, which is a very small surface area, the momentum transfer which causes drag is now much lower than before, thereby effectively reducing drag. Also, this reduces the cross-stream velocity fluctuations, which aids in momentum transfer too. The rough, sandpaper-like texture of shark and ray skin, coupled with its toughness, has led it to be valued as a source of rawhide leather, called shagreen. One of the many historical applications of shark shagreen was
Leather (comics) this time she also made friends with the female villains Giganta and Magneta. Leather (comics) Leather is a fictional character from DC Comics. Mary Kay Tanner was born in Peckinpath, Texas. Her mother often experimented with illegal and untested drugs to get high. As a result, Mary Kay was born with meta-human powers that gave her leatherlike skin and razor sharp claws. When she was 16, Leather became the leader of gang that smuggled illegal immigrants from Mexico into the U.S. Leather was captured and sent to Slabside Penitentiary. However, she was freed by the Joker and returned to smuggling