Surface age of surface renewal in turbulent interfacial transport

[1] We use direct numerical simulation to study characteristics of interfacial transfer of gas and heat in free-surface turbulence. Using Lagrangian tracing, we are able to directly quantify surface age of surface renewal for the first time. The physical meaning of surface renewal and various representations of surface age, including the use of heat as a proxy, are discussed. Results show that the Higbie penetration theory and the Danckwerts random surface renewal model are inappropriate for gas transfer.