Mathematical modelling of flow, pesticide and nutrient transport for fish-farm planning and management
Abstract In recent years, there has been a rapid growth in fish farming, particularly salmon farming, in UK and Eire coastal waters. This increase in production has also led to an awareness by the fish-farming industry that over-production could have a deleterious effect on the hydro-ecology of coastal waters, which would inhibit the maintenance of current production farming levels. In planning a fish-farm configuration for coastal basins, complex deterministic mathematical models can provide invaluable information for farm optimisation, with the models predicting the tidal current structure and solute levels in the basin. Details are given herein of a refined mathematical model for predicting tidal current and Nuvan, biochemical oxygen demand (BOD) and nitrogen levels for a proposed fish-farm configuration in a bay off the Eire coastline. The model accurately predicts field-measured velocities at two sites within the bay, and further predicts Nuvan, BOD and nitrogen levels that are well below those levels which would be known to affect adversely the hydro-ecology of the bay.
Modeling Solute Transport Using QUICK Scheme
Details are given of the refinement and application of a two‐dimensional depth integrated numerical model to predict the depth mean velocity field and the spatial concentration distribution in hydraulic basins, such as chlorine contact tanks. The model includes a refined and computationally manageable third‐order spatial finite‐difference representation of the terms describing the advective transport of a solute, with the corresponding difference scheme being particularly suited to modeling high solute gradients. The scheme is shown to yield high accuracy in comparison with the more conventional second‐order central‐difference representation, with the associated spurious wavetype distribution solute concentrations associated with high‐solute gradients being considerably reduced. The model has been applied to a laboratory hydraulic model study of plug flow through a site‐specific chlorine contact tank, with the numerical model results for various tank configurations being compared with corresponding labora...
Assessment of Ground Regeneration around Borehole Heat Exchangers between Heating Seasons in Cold Climates: A Case Study in Bialystok (NE, Poland)
Based on the experimental studies, the process of ground regeneration around the borehole loaded with brine-water heat pumps working exclusively for heating purposes in the period of four consecutive heating seasons in a cold climate was presented. The research was conducted in north-eastern Poland. The aim of the work is to verify the phenomenon of thermal ground regeneration in the period between heating seasons on the basis of the recorded data and to check whether the ground is able to regenerate itself and at what rate. It was noticed that the ground does not fully regenerate, especially during heating seasons with lower temperatures. In the analyzed period, from 22 September 2016 to 12 October 2020, the ground probably cooled irreversibly by 1.5 °C. In order to illustrate and evaluate the speed of changes in the ground, the one’s profile with an undisturbed temperature field was presented for each month of the year. The presented results can be a very important source of information for the analysis of geothermal conditions occurring in the ground. They can be used to verify mathematical models and conduct long-term simulations that allow us to see the complexity of the processes taking place in the ground.