Premium
Longitudinal dispersion in nonuniform flow
Author(s) -
Carter H. H.,
Okubo A.
Publication year - 1972
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr008i003p00648
Subject(s) - dispersion (optics) , tracer , flow (mathematics) , mechanics , estuary , point (geometry) , mathematics , environmental science , mathematical analysis , physics , geology , geometry , optics , nuclear physics , oceanography
Nonuniform flow is defined as a flow in which the velocity at any given time changes from point to point along a streamline. Such a flow occurs in an estuary in which the cross‐sectional area increases in the longitudinal or downstream direction. A general solution to the one‐dimensional equation that describes the fate of a pollutant introduced into such an estuary has not been found; only certain special solutions have been given for various simple analytical expressions for the longitudinal variation of area and longitudinal dispersion coefficient. Furthermore solutions to this equation are given in terms of the longitudinal dispersion coefficient, the value of which is not determinable a priori. A peak concentration model is developed that is applicable to estuaries and rivers whose lengths are large in comparison to their widths and depths. This model permits the estimation of the longitudinal dispersion coefficient K e from the geometry of the system and from measurements of the peak dye concentration determined by the release of a known quantity of a tracer material such as rhodamine WT. The geometry need not be specified analytically; it need be specified only numerically at the positions of the peak concentration. The tracer experiments and the manner in which the longitudinal dispersion coefficients are estimated are described. A method for estimating the applicability of the procedure is also presented.