E-Thesis 78 views 67 downloads
Hydrodynamic Loading And Vortex Formation On Inundated Masonry Bridge Models / KGOTLA MAAKWE
Swansea University Author: KGOTLA MAAKWE
DOI (Published version): 10.23889/SUThesis.71068
Abstract
This thesis presents a comprehensive investigation of hydrodynamic loading and vortex dynamics in inundated masonry bridges , combining experimental studies, analytical modeling, and numerical simulations . The research focuses on elucidating pressure variations, vortex shedding mechanisms, and vort...
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Swansea
2025
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| Institution: | Swansea University |
| Degree level: | Doctoral |
| Degree name: | Ph.D |
| Supervisor: | Reeve, D. E. |
| URI: | https://cronfa.swan.ac.uk/Record/cronfa71068 |
| Abstract: |
This thesis presents a comprehensive investigation of hydrodynamic loading and vortex dynamics in inundated masonry bridges , combining experimental studies, analytical modeling, and numerical simulations . The research focuses on elucidating pressure variations, vortex shedding mechanisms, and vortex induced vibrations (VIV) in order to advance the understanding of fluid-structure interactions and enhance the resilience of bridge structures under open channel flow. Experimental investigations employed state-of-the-art instrumentation, including pressure sensors and accelerometers , to capture pressure distributions and structural vibrations under varying flow regimes. Hammer testing was used to identify natural frequencies , while dye injection and flow visualization revealed complex vortex shedding patterns. Analytical modeling through finite element analysis (FEA) in ANSYS provided structural mode shapes and natural frequencies , validated against experimental results . Complementary computational fluid dynamics ( CFD) simulations with REEF3D further examined velocity fields , turbulence structures, and pressure dynamics , with validation confirming errors generally below 10 to 13%.The main findings indicate that Bridge Model A remains relatively stable at lower flow rates, with improved damping at higher flows, while Bridge Model B exhibits distinct resonant frequencies, negative damping, and heightened susceptibility to VIV across conditions. Frequency response analysis and damping ratio evaluations confirmed anisotropic vibrational behavior, primarily within the X-Y plane. Correlation analyses of pressure, velocity, vorticity, and turbulent kinetic energy beneath the arch barrel revealed stronger velocity-pressure and velocity-vorticity interactions in Bridge Model A, reflecting localized acceleration and coherent vortex structures, whereas Bridge Model B displayed weaker correlations associated with distributed turbulence and wake stabilization. Collectively, these insights underscore the importance of robust energy dissipation mechanisms , tailored design modifications , and accurate numerical modeling to mitigate flow-induced instabilities and ensure long-term structural safety. |
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| Keywords: |
Vortex-induced vibrations, masonry bridges, REEF3D |
| College: |
Faculty of Science and Engineering |
| Funders: |
Botswana Government |