Mixing of a passive scalar near a free surface

Lian Shen, George S. Triantafyllou, Dick K P Yue

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


We study numerically and analytically the mixing of a passive scalar in turbulent shear flow with a free surface. The Navier-Stokes and scalar mixing equations are solved by direct numerical simulation. We find that the mean concentration of the scalar exhibits a two-layer structure near the free surface: an outer layer, characterized by a fast reduction in the value of the turbulent diffusivity of the scalar, and a much thinner layer characterized by a fast reduction of the mean concentration gradient. We develop a similarity theory for the variation of the mean concentration, which agrees very well with the numerical results and provides us with scaling relations for the thickness of each layer.

Original languageEnglish (US)
Pages (from-to)913-926
Number of pages14
JournalPhysics of Fluids
Issue number4
StatePublished - Jan 1 2001


Dive into the research topics of 'Mixing of a passive scalar near a free surface'. Together they form a unique fingerprint.

Cite this