Author(s): John S. Gulliver; Martin J. Halverson

Linked Author(s): John S. Gulliver

Keywords: No Keywords

Abstract: Laboratory flume experiments on water-side controlled gas transfer,such asreaeration,are described.The experimental data are fit to Dankwerts'(1951)surface renewal model,as originally proposed by o'Connor and Dobbins(1958)foran open channel flow.The primary cause of surface renewal in flumes is pro-posed to be the upwelling of large streamwise vortices and is documented byrelating prior velocity measurements of these vortices and observations ofsurface upwellings to gas transfer measurements,A dimensionless liquid filmcoefficient(Stanton number)is related to a shear Peclet number and a shearReynolds number.The shear Reynolds number represents the effectiveness of thelarge streamwise vortices in penetrating the water surface.The proposedhypothesis is essentially a large eddy model,except that coherent structures,the large streamwise vortices,in the flow have been identified as thepredominant mechanism of surface renewal,rather than random turbulence.The1mplications of this surface renewal mechanism are discussed.

DOI:

Year: 1989