Dispersion in Turbulent Film Flow

Dispersion of miscible solutes from non-uniformly distributed instantaneous sources in two dimensional smooth open channel turbulent flows is described satisfactorily by using generalized dispersion theory wherein the coefficients of the dispersion model depend on time. The truncation of the generalized dispersion model after the first two terms is justified by comparison of results with experimental data. The behavior of the convective coefficient, k1, (t) and the dispersion coefficient, k2(t), for turbulent flow is studied in detail for all values of time, k1(t) and k2(t) reach asymptotic constant values at t 0.5 y2 m,/ε at which time the generalized dispersion model reduces to the Taylor constant coefficient model. Area mean concentration distributions predicted by the generalized dispersion theory agree with the experimental data of Fischer (1966) rather closely and the theoretical results agree with the data much better than those from Taylor's model.