Skin Friction
Skin friction arises from the friction of the fluid against the "skin" of the object that is moving through it. Skin friction arises from the interaction between the fluid and the skin of the body, and is directly related to the area of the surface of the body that is in contact with the fluid. Skin friction follows the drag equation and rises with the square of the velocity.
Skin friction is caused by viscous drag in the boundary layer around the object. There are two ways to decrease skin friction: the first is to shape the moving body so that smooth flow is possible, like an airfoil. The second method is to decrease the length and cross-section of the moving object as much as is practicable.
Read more about this topic: Friction
Famous quotes containing the words skin and/or friction:
“... the trouble is that most people in this country think that we can stay out of wars in other parts of the world. Even if we stay out of it and save our own skins, we cannot escape the conditions which will undoubtedly exist in other parts of the world and which will react against us.... We are all of us selfish ... and if we can save our own skins, the rest of the world can go. The best we can do is to realize nobody can save his own skin alone. We must all hang together.”
—Eleanor Roosevelt (1884–1962)
“We have got onto slippery ice where there is no friction and so in a certain sense the conditions are ideal, but also, just because of that, we are unable to walk. We want to walk so we need friction. Back to the rough ground!”
—Ludwig Wittgenstein (1889–1951)