Infrastructure Engineering - Theses
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ItemFree surface flow in a circular conduit: a theoretical and experimental investigation of the influence of velocity distributions on flow behaviour( 1963)General Introduction: Since Chezy first proposed his well known equation for uniform flow in open channels, many other formulae have been suggested, either to replace the Chezy expression or form determining the value of the coefficient C. Perhaps the major objection to the use of these formulae is that no account is taken of the variation of the boundary effects with Reynolds number — although in some cases this is done indirectly by relating Chezy’s C to the hydraulic mean radius. Following more recent work, notably by Prandtl, there have been attempts to produce relationships between Chezy’s C, Reynolds number and a roughness parameter, (similar to those which exist for pipe flow) but these habe not been generally applied as the effects of the free surface and unsymmetrical flow conditions have not yet been fully evaluated.
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ItemMathematical modelling for the management of waste water systems( 1978)A need is shown to exist for a general approach to the management of the wastewater system in modern cities. This system, comprising sewage treatment plant, outfalls and receiving waters proves to be complex when viewed over planning periods of fifty years or more. A general mathematical model is, therefore, described which provides a simple framework for the analysis of such systems. In general, it is seen that the mathematical model will use particular sub-models for particular investigations. The ‘output’ from the model is a 'cost effectiveness' curve which is an intelligible presentation of the costs of the "best" options and their effects on water quality. Decision making is seen to be a political task, the costs and effects of which can be made clearer to the public, too, by moans of the cost-effectiveness curve. A case study is presented concerning the major sewage treatment system of Melbourne, Australia. This system discharges its effluent into Port Phillip Bay, which in the main, does not suffer from pollution problems at present. The model proposed for Port Phillip Bay comprises two models - a water quality model and an optimization model. The water quality model itself comprises three sub-models, a hydrodynamic model, a transport model and a model of phytoplankton growth. The hydrodynamic model is based on the two dimensional finite difference scheme proposed by Leendertse (1967) and provides information on depth integrated velocities and water levels. These are used, in turn, by a Lagrangian transport model in which the dispersion of a patch of pollutant is simulated by a cloud of computational particles. The transport information determined by this model is then passed on to a model of phytoplankton growth in the Bay. This model takes into account the effects of the nutrients of nitrogen and phosphorous forms and also the predation of zooplankton.