Bradford Scholars

Bradford Scholars is the University of Bradford online research archive. Access is free to anyone interested in research being conducted at Bradford. In the repository you will find a range of materials from journal articles and conference papers to research reports and theses.

Contact the repository team via openaccess@bradford.ac.uk with any queries about Open Access or how to deposit your research papers.

Bradford Scholars is powered by DSpace (V7). DSpace accessibility statement and WCAG 2.2 conformance report.

Communities in Bradford Scholars

Select a community to browse its collections.

Recent Submissions

  • PublicationOpen Access
    Turbulence Modelling of Tidal Currents in Rectangular Harbours
    Hakimzadeh, Habib; Falconer, Roger A.
    In this study turbulence refinements have been made to existing computational models for the prediction of currents and water levels in coastal and estuarine waters via the numerical solution of the depth- and layer-integrated Reynolds equations. As most flows in practice are always turbulent, it is necessary to try and model the turbulence as accurately as possible. Various turbulence models including the mixing length, k-s and algebraic stress turbulence models all adopting a time average statistical approach, and the Smagorinsky model of the Large Eddy Simulation type were considered in a 2-D model. Likewise, the two-layer mixing length and the k-s turbulence models were included in a 3-D model to calculate the vertical Reynolds stresses. As for the hydrodynamic equations, the finite difference method has been used for the discrete equations of the turbulence parameters. Likewise, the Alternating Direction Implicit scheme has again been used for solving the discretized turbulence equations. In the hydrodynamic equations the advective acceleration terms have been treated using the third-order upwind scheme, whereas the counterpart terms in the turbulence equations have been treated using the exquisite scheme. In the finite difference representation various closed boundary conditions, including the no-slip, semi-slip and partial-slip, have been considered for the turbulence diffusion terms in the hydrodynamic equations and in using zero-equation turbulence models. These closed boundary conditions have been found to lead to a significant difference in the predicted flow patterns, both in the 2-D and 3-D models. However, in using more sophisticated turbulence models only the common no-slip closed boundary condition has been used for the turbulence diffusion terms as well as the turbulence parameters. The modified 2-D model has been applied to the predictions of tidal flow in rectangular harbours with large and small aspect ratios, as well as to a practical case study (i.e. Rattray Island), whereas the refined 3-D model has been applied to the predictions of steady state flow in a channel, wind-induced currents in a channel, tidal flow in rectangular harbours and steady flow in a practical case study (i.e. Blithfield Reservoir). The predicted numerical model results have been compared with the measured laboratory and field data and an encouraging degree of similarity has been obtained for all of the case studies. In particular, the partial-slip condition, incorporated with the zero-equation turbulence model, gave close agreement with the experimental data. More sophisticated turbulence models were found to give closer agreement with the experimental data.
  • PublicationOpen Access
    Numerical Modelling of Geomorphological Processes in Estuarine Waters
    Kolahdoozan, Morteza; Falconer, Roger A.
    Numerical modelling of geomorphological processes in rivers, estuaries, harbours and coastal waters is an efficient means of predicting bed level changes for further use in planning the maintenance and management of these areas. Nowadays, quasi-3D models are increasingly popular, particularly with the rapid progress in the power of modem day computers. In this thesis the development and application of two-dimensional and three-dimensional numerical models for predicting geomorphological processes in estuarine waters have been under consideration, with particular emphasis on the unsteady initiation of motion criteria for sediment particles. The governing hydrodynamic, sediment transport and bed level change equations are reviewed in their differential form by using the conservation laws of mass and momentum for fluid and sediment particles. Then the depth integrated and layer integrated form of these equations are derived for the domain. Different solution procedures for developing the geomorphological model are discussed in this thesis according to the nature of flow for different computational domains. A new unsteady criteria for the initiation of motion has been proposed based on the mathematical analysis of the physical processes. In this hypothesis, it is assumed that tides can be approximated by a sinusoidal wave and by applying Newton's second law then the resulting time varying forces acting on sediment particle can be calculated. The proposed criteria for the initiation of motion have been included in the geomorphological models, namely GEO-DIV AST and GEO-TRIV AST, which have been developed for two-dimensional and three-dimensional geomorphological simulations based on depth integrated and layer integrated algorithms respectively. A series of experimental tests have been undertaken in a laboratory rectangular harbour to verify the geomorphological model. The measured bed level changes for the various values of related parameters are presented for the verification and validation of numerical models and proposed criteria. The numerical models have been run for several case studies including: (1) migration in a trench, (2) bed level changes in a partially closed channel, (3) geomorphological development in the laboratory rectangular harbour, and (4) geomorphological developments in the Humber Estuary due to tidal currents. Predicted velocity, sediment concentration distributions and bed level changes have been illustrated to show the geomorphological developments in the corresponding computational domain. The predicted velocity, sediment transport and bed level changes have been compared with measured laboratory and field data and also numerical results of reported models in the literature, with an encouraging degree of similarity being observed for all cases, confirming the validation of the proposed new criteria for the initiation of motion and the GEO-TRIV AST numerical model for successful three dimensional estuarine flow simulations.
  • PublicationOpen Access
    Relocations of Hindutva: Hindu Nationalism Under Modi 3.0
    (2025-12-01) Nielsen, K.B.; Nilsen, A.G.; Selvaraj, M. Sudhir
    In this special issue introduction, we use the 2024 Indian national elections as our entry point for critically assessing the configuration and direction of Hindu nationalism as a hegemonic project under Modi 3.0 – a project that has forged an intimate connection between neoliberal accumulation strategies and ‘Hindutva’ as a vehicle for ideological legitimation. Rather than seeking to determine whether the elections mark a setback or a consolidation for Narendra Modi’s Bharatiya Janata Party (BJP), we ask how and to what effect they signal a more profound geographical and sociological relocation of the wider Hindu nationalist project. Working with the notion of ‘relocations’, we seek to capture the simultaneous yet uneven contraction and expansion of Hindutva’s footprint across multiple geographies and demographic categories, both prior to and after 2024. Drawing on the granular state-level analyses contained in the contributions to this special issue, we argue that while contemporary Hindu nationalist politics displays a considerable degree of flux, fluidity, and in some cases even vulnerability, its unfolding relocations in crucial ways contribute to the continued reproduction of Hindu nationalist hegemony under Modi 3.0.
  • PublicationOpen Access
    Evaluation of heat extraction using compact shallow ground heat panels with the interaction of stormwater- a residential case study
    (Elsevier, 2026-03-01) Mohamed, Mostafa; Abdullah, Abubaker; El-Kezza, Omar; Abdel-Aal, M.; Schellart, A.; Tait, S.
    A bespoke parallel shallow horizontal Ground Source Heat Pump system (GSHP) with a small footprint (50 m2) was installed to provide space heating and domestic hot water for a residential house in the North of England. The shallow GSHP was combined with a storm water infiltration trench and both were installed with an adjacent control house which was fitted with a standard gas boiler for space heating and hot water. Up to 350 metres of High Density Polyethylene (HDPE) pipe with an external diameter of 40 mm connected in 2 parallel compact panels was used at the front and back of the house with the GSHP. The paper aims to (i) present data for the response of the ground to heat extraction using shallow ground heat panels and (ii) analytically model the heat gain in the ground heat exchanger panel, accounting for the thermal resistivity between the heat exchanger pipes and the surrounding soil, as well as the varriations in ground temperature and thermal conductivity. Internal and external ambient air temperatures, rainfall, coolant flow rate, coolant temperature, ground temperature and ground water level were monitored for a full year. The comprehensive field data were analysed to demonstrate the ground response and evaluate the performance of the shallow parallel ground heat extraction panels. Field data indicated that rainwater enhanced heat extraction and caused temporary increase in the ground temperature. Results from the analytical model are compared with measured temperature at five points on the ground heat extraction panel. The model showed good levels of predictive performance of the coolant temperature along the ground panel. However, it was noted that the model overestimates the coolant temperature at the centre point of the ground panel.
  • PublicationOpen Access
    Thermal Performance of Geopolymer Concrete Energy Piles
    (Springer, 2026-02-01) Elkezza, Omar; Hasan, M.; Alhawat, Musab; Khan, A.; Mohamed, M.; Sheehan, Therese
    This study evaluates the thermal perfor-mance and environmental impacts of energy geo-piles constructed using geopolymer concrete (GPC) incorporating 30% electric arc furnace slag (EAFS), in comparison with conventional ordinary Port-land cement concrete (OPCC). The study involved comprehensive experimental testing and numerical modelling to assess heat-transfer efficiency, thermal deformation characteristics, and the carbon footprint of each material system. Two full-scale prototype piles were built and tested; one made from EAFS-GPC and the other from OPCC. Both concrete types exhibited comparable mechanical performance. Results show that piles constructed using EAFS-GPC exhibited higher thermal conductivity, resulting in a 14% improvement in the heat-transfer efficiency compared with the measurements recorded on the OPCC pile. In addition, the thermal expansion coef-ficient of EAFS-GPC piles was 17% lower than that of the normal Portland concrete pile, thereby reduc-ing susceptibility to lateral earth pressures. The sur-rounding soil reached an 8% higher steady-state temperature, indicating more efficient heat exchange. Importantly, the use of GPC led to a 45% reduction in CO2 emissions, demonstrating significant environmental benefits. The numerical model results were in close agreement with the laboratory measurements, with a maximum deviation of 7.2%. The study findings confirm that EAFS-enhanced GPC is a high-performance, low-carbon material for next-generation energy geo-piles, with optimal behaviour achieved when the pile thermal conductivity matches or exceeds that of the adjacent soils.
Show more