a process for reducing skin friction , inhibiting the effects of liquid turbulence , and decreasing heat transfer in a system involving flow of a liquid along a surface of a body includes applying a substantially integral sheet of a gas , e . g ., air , immediately adjacent to the surface of the body , e . g ., a marine vehicle , which has a longitudinally grooved surface in proximity with the liquid and with a surface material having high contact angle between the liquid and said wall to reduce interaction of the liquid , e . g ., water , with the surface of the body , e . g ., the hull of the marine vehicle .