Options
Keenahan, Jennifer
Preferred name
Keenahan, Jennifer
Official Name
Keenahan, Jennifer
Research Output
Now showing 1 - 7 of 7
- PublicationA Numerical Study of the Effect of Wind Barriers on Traffic and the Bridge Deck(Civil Engineering Research Association of Ireland, 2020-08-28)
; ; Wind actions can have a great impact on both bridges and traffic on bridges. However, structures designed to shelter the traffic from wind can influence the aerodynamic performance of the bridge deck, especially for long-span bridges. This study compares the effect of non-perforated walls and perforated walls used as wind barriers for traffic by conducting Computational Fluid Dynamics (CFD) simulations on three-dimensional geometries of a four-lane bridge deck. Steady-state simulations employ the Reynolds-Averaged Navier Stokes (RANS) method with the k-epsilon turbulence model and all simulations use parallel computing. An open-sourced software OpenFOAM is used.197 - PublicationA numerical study on the sheltering effects of the central wind barriers on the Rose Fitzgerald Kennedy Bridge(CERAI, 2022-08-26)
; ; ; ; This study aims to examine the sheltering effects of central wind barriers installed near the pylons of the Rose Fitzgerald Kennedy Bridge. A full-scale Computational Fluid Dynamics (CFD) model is developed, which includes high-precision geometries of the bridge and the terrain. Simulations using this model are performed at realistic wind conditions as boundary conditions are mapped from mesoscale Weather Research and Forecasting (WRF) simulations. Wind velocities at multiple locations on the bridge predicted by the CFD simulations are compared with field measurement data where a good agreement is reached. The validated model is then applied with bridge geometries with and without the central wind barriers at high wind conditions. Comparisons between these two groups of simulations show that the wind barriers can effectively reduce wind velocities on traffic lanes near the pylon, which validates the current design of the barriers on the bridge.41 - PublicationCFD Modelling of Helicopter Downwash and Assessment of its impact on Pedestrian Comfort(2018-08-30)
; ; ; ; This study used computational fluid dynamics (CFD) study to investigate the impact of helicopter downwash on pedestrian comfort. The initial stage of the study involves the development of a helicopter downwash model that was compared to experimental values which showed some degree of coherence with areas situated downstream of the helicopter rotor. The initial stage was used to find suitable modelling parameters and an adequate resolution of computational mesh to produce a reliable helicopter downwash model. The final stage of the study is to integrate a helicopter in a built environment and assess the impact of downwash on pedestrian comfort. The concluding stage of the study showed that helicopter downwash effects can impose discomforting conditions in the immediate vicinity of the helicopter along with some minute propagating effects further downstream. Although its magnitude is smaller compared to effects of prevailing wind a local mitigation must be separately planned to deal with the effects of helicopter downwash.495 - PublicationQuantifying the impact of bridge geometry and surrounding terrain: wind effects on bridges(ICE Publishing, 2023-05-15)
; ; ; ; The safety and serviceability of long-span bridges can be significantly impacted by wind effects and therefore it is crucial to accurately estimate them during bridge design. This study develops full-scale 3-Dimensional CFD (computational fluid dynamics) simulation models to replicate wind conditions at the Rose Fitzgerald Kennedy Bridge in Ireland. The neglection of bridge geometries and the use of small scales in previous studies are significant limitations, and both the bridge geometry and surrounding terrain are included here at full-scale. Input values for wind conditions are mapped from weather simulations that apply the Weather Research and Forecasting (WRF) model. Wind velocities at four different points calculated by CFD simulations are compared with corresponding data collected from SHM field measurements. The calculated time-averaged wind velocities at four different locations on the bridge are shown to have relative differences of less than 10% to the measured wind velocities by anemometers 90% of the time. The maximum relative difference among all comparisons was only 15%, shown to be partially due to the inclusion of the full bridge and terrain geometry.2Scopus© Citations 1 - PublicationAssessing the Capability of Computational Fluid Dynamics Models in Replicating Wind Tunnel Test Results for the Rose Fitzgerald Kennedy BridgeDespite its wide acceptance in various industries, CFD is considered a secondary option to wind tunnel tests in bridge engineering due to a lack of confidence. To increase confidence and to advance the quality of simulations in bridge aerodynamic studies, this study performed three-dimensional RANS simulations and DESs to assess the bridge deck aerodynamics of the Rose Fitzgerald Kennedy Bridge and demonstrated detailed procedures of the verification and validation of the applied CFD model. The CFD simulations were developed in OpenFOAM, the results of which are compared to prior wind tunnel test results, where general agreements were achieved though differences were also found and analyzed. The CFD model was also applied to study the effect of fascia beams and handrails on the bridge deck aerodynamics, which were neglected in most research to-date. These secondary structures were found to increase drag coefficients and reduce lift and moment coefficients by up to 32%, 94.3%, and 52.2%, respectively, which emphasized the necessity of including these structures in evaluations of the aerodynamic performance of bridges in service. Details of the verification and validation in this study illustrate that CFD simulations can determine close results compared to wind tunnel tests.
135Scopus© Citations 5 - PublicationInvestigation of helicopter downwash effect on pedestrian comfort using CFD(ICE Publishing, 2019-12-04)
; ; ; ; ; This study employed computational fluid dynamics (CFD) to investigate the impact of helicopter downwash on pedestrian comfort in a representative low-rise streetscape. A time-averaged approach was adopted, where propulsion from the helicopter blades was included using the so-called rotor disc method, as implemented in the open-source software OpenFoam. The modelling approach was validated by comparing downstream air velocities with experimental measurements. The effect of helicopter downwash on pedestrian comfort in a low-rise built environment, representative of an Irish city streetscape, was then analysed. It was found that pedestrian comfort significantly decreased in the immediate vicinity of the helicopter, while minor propagating effects were felt further downstream. The effects of building height, street width and prevailing winds were then examined. In general, it was found that taller buildings tended to improve street-level pedestrian comfort, while narrow streets surrounded by tall buildings tended to funnel the downwash towards the street level, decreasing pedestrian comfort. The main conclusion is that although the effect of helicopter downwash is smaller in magnitude compared with that of prevailing winds, a local mitigation must be established to deal with it.Scopus© Citations 3 156 - PublicationWind-Induced Phenomena in Long-Span Cable-Supported Bridges: A Comparative Review of Wind Tunnel Tests and Computational Fluid Dynamics ModellingEngineers, architects, planners and designers must carefully consider the effects of wind in their work. Due to their slender and flexible nature, long-span bridges can often experience vibrations due to the wind, and so the careful analysis of wind effects is paramount. Traditionally, wind tunnel tests have been the preferred method of conducting bridge wind analysis. In recent times, owing to improved computational power, computational fluid dynamics simulations are coming to the fore as viable means of analysing wind effects on bridges. The focus of this paper is on long-span cable-supported bridges. Wind issues in long-span cable-supported bridges can include flutter, vortex-induced vibrations and rain–wind-induced vibrations. This paper presents a state-of-the-art review of research on the use of wind tunnel tests and computational fluid dynamics modelling of these wind issues on long-span bridges.
116Scopus© Citations 17