Degree
Doctor of Philosophy (PhD)
Department
Civil and Environmental Engineering
Document Type
Dissertation
Abstract
Low-rise buildings are a main type of residential buildings that are widely used across the United States, yet are usually susceptible to wind induced damages. In coastal areas, the low-rise buildings are elevated to mitigate the flooding and storm impacts, which, however, exposes them to increased wind forces. However, the relevant specifications for design and construction are lacking or incomplete. To create resilient residential communities facing extreme windstorms, there is an urgent need to study the wind effects on the elevated low-rise buildings.
In the community of computational wind engineering(CWE), Large Eddy Simulation(LES) is an accurate and efficient method to simulate wind effects and wind-structure interaction. In this research, the LES technique is used to model and better understand the wind pressures on low-rise wooden houses. When using LES, an appropriate inflow, which represents the prescribed turbulence characteristics, is crucial for obtaining accurate simulation resutls. Among the developed inflow generation methods, the Discretizing and Synthesizing Random Flow Generator(DSRFG) inflow generation method is commonly used because it can easily control the Power Spectral Density(PSD) and turbulence intensities. However, its computational cost is significant compared to the subsequent LES. Therefore, its efficiency needs to be improved. This dissertation develops an accurate and efficient DSRFG method via nonuniform energy spectra discretization. The computational cost is significantly reduced but the accuracy is improved. Based on the improved DSRFG method, wind pressures on elevated low-rise buildings are simulated and the corresponding results are validated by experimental data from Florida International University(FIU) Wall of Wind(WoW) Experimental Facility(EF). The discrepancies between the LES results and experimental data are examined and explained. Meanwhile, different Sub-Grid Scale(SGS) models are adopted in LES to compare the impacts of SGS models on the simulation results. Based on the validated LES model, turbulence intensity effect on wind pressures on low-rise houses is studied. By changing the streamwise and spanwise turbulence intensities, their effects on the pressure fluctuations are analyzed to better understand the aerodynamics of the elevated low-rise buildings exposed to winds with different turbulence intensities. It is found that the peak suction pressure in the flow separation zone is the most sensitive to the changing of the streamwise turbulence intensities.
To summarize, an improved DSRFG method is proposed in this dissertation and is used to simulate wind pressures on the isolated low-rise building. The results can help better understanding the wind effects on the structures to build more resilient structures facing hurricane disasters.
Date
1-15-2024
Recommended Citation
Wang, Xiangjie, "Large Eddy Simulation of Wind Effects on Elevated Low-rise Buildings via an improved DSRFG Inflow Generation Method" (2024). LSU Doctoral Dissertations. 6331.
https://repository.lsu.edu/gradschool_dissertations/6331
Committee Chair
Sun, Chao