Modelling Velocity Distribution in 3-D for Nun River, Niger Delta Nigeria

Abstract

In this study, hydrodynamics and sediment concentration equations of partial differential in 3-dimensions were solved using finite difference methods, the Crank Nicolson procedure to predict both sediment concentration and velocity profile of Nun River. The computer software (EKU2.8) which is a modification of the Navier Stoke’s equations was employed for discretization of Nun River stretch of 2,000 m into 2,245 rectangular meshes and simulation of the river’s flow velocity distribution. The code was validated by using the field water current measurements obtained from a selected stretch of the river. Average predicted velocities of 0.85 m/s, 1.542 m/s and 0m/s compared favorably with 0.8m/s, 1.475 m/s and 0.09m/s obtained from field measurement for upstream, midstream and downstream boundaries. The predicted results have approximate correlation coefficients of 0.96 for velocity distribution using Pearson product-moment method. The model proved very useful in predicting the velocity distribution of Nun River; higher versus lower velocities at inner and outer bends, with resultant effect of erosion and sediment deposition accordingly. The result of this study may be considered an important contribution to the improvement of sediment and erosion risk management.