This is also why winter precipitation sometimes falls as freezing rain. Weather systems can blow mild air up and over the top ...

Frictional drag comes from friction between the fluid and the surfaces over which it is flowing. This friction is associated with the development of boundary layers, and it scales with Reynolds number ...

Within the boundary layer, adjacent layers of fluid are in relative motion, and because all fluids have viscosity, there will be friction between the layers as they slide over each other. In other ...