Engineering Commons^™

A Computational Framework For Aerodynamic And Aeroelastic Modeling Of Wind Loads On Tall Buildings, Abiy Fantaye Melaku

Electronic Thesis and Dissertation Repository

Driven by the burgeoning growth of computing power over the last few decades, the capability of computational fluid dynamics (CFD) to simulate turbulent flows of practical interest has progressed rapidly. In the past, a notable research effort has been dedicated to applying CFD for modeling wind loads on structures, particularly for tall buildings. However, the current state of CFD for wind load evaluation of tall buildings using Large-Eddy Simulation (LES) has several critical challenges, including the treatment of atmospheric boundary layer (ABL) flow conditions, turbulence modeling of separated flows around buildings, and simulation of wind-structure interaction for dynamically sensitive buildings. …

Experimental Analysis And Numerical Investigation Of Aerodynamics Of Elevated Structures, Nourhan Abdelfatah

FIU Electronic Theses and Dissertations

The vulnerability of low-rise residential buildings to extreme wind events, such as hurricanes, is an escalating concern due to the frequent failures and losses. Elevated low-rise structures are constructed to reduce the hydrodynamic load from surges and flooding during hurricanes. However, due to the current lack of information, wind loading on elevated coastal structures is not adequately addressed in current international guidelines. To address this knowledge gap, large-scale experimental studies were conducted to precisely determine wind effects on elevated houses with different numbers of stories and varying stilt heights. In this study, comparisons are presented on various tested configurations to …

A Partial-Turbulence Approach To Estimate Peak Wind Loads On Low-Rise Building Roofs, Yitian Guo

Electronic Thesis and Dissertation Repository

Quasi-steady (QS) theory is a commonly-used tool in wind engineering for the assessment of wind loads on structures induced by large-scale gusts. However, the QS-based approach tends to underestimate peak loads significantly since it fails to capture the effects of small-scale and body-generated turbulence. The objective of this thesis is to develop a method to estimate peak wind loads on low-rise roofs based on a partial-turbulence approach, i.e., using the QS vector model for loads induced by large-scale fluctuations from the incident flow, and a separate statistical model to account for the effects due to body-generated turbulence.

Wind tunnel tests …

Effects Of Corner Radii On Wind Tunnel Testing Of Low-Rise Buildings, Kytin Kwan

Electronic Thesis and Dissertation Repository

Wind effects on buildings are commonly studied by testing 3D printed building models in a wind tunnel. A challenge with 3D printing is that the edges of these models may not be perfectly sharp, but rounded with a radius of curvature, R. It is well known that when edges are significantly rounded, the aerodynamics of the building can be altered (Robertson, 1991; Mahmood 2011), leading to inaccurate predictions of full-scale surface pressures and wind loads. However, there is presently no guidance on model edge radii prescribed in wind tunnel testing standards such as ASCE 49-12. The objective of the present …

Investigating Scale Effects On Analytical Methods Of Predicting Peak Wind Loads On Buildings, Mohammadtaghi Moravej

FIU Electronic Theses and Dissertations

Large-scale testing of low-rise buildings or components of tall buildings is essential as it provides more representative information about the realistic wind effects than the typical small scale studies, but as the model size increases, relatively less large-scale turbulence in the upcoming flow can be generated. This results in a turbulence power spectrum lacking low-frequency turbulence content. This deficiency is known to have significant effects on the estimated peak wind loads.

To overcome these limitations, the method of Partial Turbulence Simulation (PTS) has been developed recently in the FIU Wall of Wind lab to analytically compensate for the effects of …

Influence Of Turbulence On The Aerodynamics Of Low-Rise Buildings, Fakhruzzaman Arif

Electronic Thesis and Dissertation Repository

During extreme wind events, roofing failures may lead to damage of the whole structure. In order to alleviate the effect, surface pressure coefficients on the roofs have been extensively investigated. This research aims to determine the roof pressures acting on low-rise buildings with consideration of the effects of turbulence (terrain). Pressure measurements, as well as wind speed data, were taken at the Boundary Layer Wind Tunnel Laboratory (BLWTL) of the University of Western Ontario (UWO) to examine the influence of turbulence level (i.e., terrain condition) on the critical wind directions corresponding to the largest surface roof pressure coefficients for various …

Estimation Of Turbulence Effects On Wind-Induced Suctions On The Roof Of A Low-Rise Building, Chieh-Hsun Wu

Electronic Thesis and Dissertation Repository

The effects of turbulence in the atmospheric boundary layer (ABL) on surface pressures of a typical low-rise building roof are investigated in this thesis. A 1/50 geometrically-scaled model of the Texas Tech University Wind Engineering Field Research Lab (WERFL) building model is used for pressure measurements in wind tunnel experiments. ABL wind turbulence intensities ranging from about 10% to 30%, and length scales ranging from 6 to 12 times of the building height (H) are generated. The effects of ABL turbulence on the mean roof pressures within the separated flow are explained from the time-averaged Navier-Stokes equations. The pressure fields …

Engineered Earthen Masonry Structures For Extreme Wind Loads, Mabel Cristina Cuellar-Azcarate

Theses and Dissertations

Stabilized earthen masonry (SEM), which is built with compressed stabilized earthen blocks (CSEB) and mortar, is emerging as a construction system for affordable, sustainable and high-quality dwellings. Compelling features of earthen masonry are local availability of suitable soils, thermal insulation properties, humidity control within healthy ranges, and relatively low carbon footprint. SEM is also appealing for the construction of affordable houses in rural areas and farmlands, where underrepresented and underprivileged groups often live. In fact, the lack of affordable housing is an issue across the United States where low-income families are most affected, often committing more than half of their …

Wind-Induced Pressures In Air Permeable, Double-Layer Roof Systems In Regions Of Separated Flow, Jeong Hee Oh

Electronic Thesis and Dissertation Repository

This thesis is concerned with the wind-induced pressure distribution acting on air permeable, double-layer roof systems placed on low-rise buildings. Because of the pressure transmission into the cavity between layers, the pressure difference in the double-layer systems differs significantly from that in a single layer. The interior pressures (in the cavity between layers) are highly correlated with external pressures at the openings on the external surface of the outer layer and thereby, the net wind load for the design of the outer layer is considerably reduced by the pressure equalization between the external and internal surfaces of the outer layer. …

Response Of A Two-Story Residential House Under Realistic Fluctuating Wind Loads, Murray J. Morrison

Electronic Thesis and Dissertation Repository

Severe wind storms such as tropical cyclones, tornados, downbursts etc. can cause significant damage to infrastructure. Damage surveys following these events have shown that the roofs of residential, wood-frame construction are particularly vulnerable to failures. While damage surveys provide detail information of what components fail, they cannot provide the loads at which these failures occurred or how they initiated. Wind tunnel pressure models provide detailed information of the wind loads on buildings, however, they are not able to predict failures or how these loads are transferred through the structure. In order to better understand the response of wood framed houses …

Wind Loads For Petrochemical Structures, Samuel Amoroso

LSU Doctoral Dissertations

Techniques currently available to practicing engineers for estimating wind loads for petrochemical structures have little theoretical or experimental basis. This dissertation research is an effort to expand the understanding of wind effects on petrochemical and other, similar structures. Petrochemical structures introduce geometric scales into wind tunnel model simulations below what are common for enclosed structures. Wind tunnel experiments were performed to help determine whether this will introduce problems in achieving dynamic similarity between models and prototypes. The experiments did not reveal any clear indication that petrochemical structures cannot be modeled in wind tunnels at scales similar to those used for …

Wind Loads On Multiple Cylinders Arranged In Tandem With Effects Of Turbulence And Surface Roughness, Xianzhi Liu

LSU Master's Theses

The goal of this study is to investigate the characteristics of mean drag and lift forces for a series of cylinders arranged in tandem with varying flow turbulence and surface roughness. This goal was fulfilled by building a wind tunnel test section capable of generating both smooth flow and turbulent flow, and by adopting cylinder models with certain types of surface roughness as well as the smooth surface. In both smooth flow and grid-turbulence flow conditions, single cylinders as well as multiple cylinders were tested. The tested Reynolds number ranged from 2.7×104 to 8.6×104. For multiple-cylinder tests, a majority of …