Prediction Of Longitudinal Dispersion Coefficient Research Articles

Prediction of longitudinal dispersion coefficients in natural rivers using genetic algorithm

A new expression for the prediction of longitudinal dispersion coefficient in natural rivers, using genetic algorithms, is proposed. The expression uses hydraulic and geometric characteristics of rivers, which are readily available. For performance evaluation, using published field data, results of coefficient prediction by the new expression and by the other reported expressions are compared. According to various performance indices, it is concluded that the new formula predicts the longitudinal dispersion coefficient more accurately. Sensitive analysis performed on input parameters indicates the ratio of the cross-sectional mean velocity to the bottom shear velocity to be the most influencing parameter for accurate prediction of the longitudinal dispersion coefficient.

Water quality hazards and dispersion of pollutants

Mixing Models for Water Quality Management in Rivers: Continuous and Instantaneous Pollutant Releases.- Three-Dimensional Model of Flow and Mixing Processes in Open Channels.- Horizontal Mixing in Shallow Flows.- On the Theoretical Prediction of Longitudinal Dispersion Coefficients in a Compound Channel.- Application of a Transient Storage Model to Meandering Channel Studies of Solute Transport and Dispersion.- Experimental Study of Travel Times in a Small Stream.- Migration of Floating Particles in a Compound Channel.- Persistence of Skewness of Concentration Distribution.- Moments and Analytical Solution of Coupled Equation Describing Transport of Pollutants in Rivers.- Influence of Hyporheic Exchange on Solute Transport in a Highly Hydropower Regulated River.- Models of Hyporheic Contamination by Non Reactive Solutes, Metals and Colloids.- The Flow in Groyne Fields.

The determination and prediction of longitudinal dispersion coefficients in a narrow, shallow estuary

Measurements of velocity and salinity for parts of a flood and an ebb tide in the Conwy estuary have been used to evaluate the time-dependent longitudinal dispersion coefficients due to vertical and transverse oscillatory shear effects. The values have been compared with semi-analytical predictive formulae. Simple empirical expressions are suggested for relating the dispersion coefficients to hydraulic parameters for the conditions observed.