diffusion velocity

diffusion velocity

[də′fyü·zhən və′läs·əd·ē] (fluid mechanics) The relative mean molecular velocity of a selected gas undergoing diffusion in a gaseous atmosphere, commonly taken as a nitrogen (N2) atmosphere; a molecular phenomenon that depends upon the gaseous concentration as well as upon the pressure and temperature gradients present. The velocity or speed with which a turbulent diffusion process proceeds as evidenced by the motion of individual eddies.