Development and application of an integrated hydro-environmental model for predicting the distribution of nutrients in estuarine and coastal waters

The integrated model is finally applied to simulate the hydro-environmental processes in the Loughor Estuary to find out the contribution of different pollution sources on the receiving water nutrient concentration levels, and the influences of pollutant discharging schemes and temperature. The results show that the refined model is accurate and provides a valuable state-of-the-art novel tool for predicting improved nutrient concentration distributions in estuarine and coastal waters.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Large-eddy simulation of supercritical free-surface flow in an open-channel contraction

Large-eddy simulations (LES) of supercritical flow in a straight-wall, open-channel contraction of 6° and contraction ratio of 2:1 are performed. The LES code solves the filtered Navier-Stokes equations for two-phase flows (water-air) and employs the level-set method. The simulation was validated by replicating a previously reported experiment. Contours of the time-averaged velocities indicate that the flow loses energy and momentum in the contracting channel. Further, secondary currents in the contraction are redistributing momentum and are responsible for local up-and down-flows. The turbulent kinetic energy reaches very high values at the entrance of the contraction, mainly contributed by the streamwise normal stress. The flow contains coherent turbulence structures which are responsible for carrying low-momentum from the bed and the water surface towards the channel centre. Flow deceleration results in significant turbulence anisotropy in the contracted section. It is shown that mainly pressure drag contributes to the energy loss in the contraction