Laboratory Wind Testing
Introduction: Wind tunnel testing is a fundamental concept in wind engineering, involving subjecting test models to controlled airflow at varying wind direction angles. However, while wind tunnels, such as Boundary Layer Laboratories (BLLs), provide valuable insights, they have inherent limitations in accurately simulating turbulence and addressing scale issues. These limitations prompt the need for a more comprehensive approach to wind testing. This page aims to highlight the significance of BLL testing while showcasing the role of the Large-Scale Open Jet (LSOJ) testing facility at LSU in bridging the gap between wind tunnel experiments and realistic full-scale outdoor testing.
Boundary Layer Laboratories (BLLs): To simulate the lower portion of the atmospheric boundary layer extending from the
Earth's surface, specialized wind tunnels known as BLLs are utilized. BLLs can be
categorized as open-loop or closed-loop systems, with the latter being more energy-efficient
due to recirculation of airflow. Specially designed vanes in closed-loop BLLs redirect
airflow, minimizing turbulence and power loss, leading to cost-effective operations.
BLLs play a crucial role in modeling straight-line winds and replicating atmospheric
boundary layer profiles through passive or active management strategies. They enable
wind impact studies on various structures, including buildings, bridges, towers, energy
infrastructure, solar panels, wind turbines, power transmission lines and towers,
wind comfort, ventilation systems, wind energy, air pollution dispersion, internal
pressure studies, crosswind effects on vehicles, wind effects on sailing yachts, cable
aerodynamics, and more.
Limitations of Wind Tunnel Testing: While wind tunnel testing provides controlled
airflow for precise model testing, it faces limitations in accurately simulating turbulence
and addressing scale issues found in real-world atmospheric conditions. Replicating
complex turbulence patterns poses a challenge, and scaling down large structures for
wind tunnel experiments can introduce uncertainties and compromise result fidelity.
The Role of Large-Scale Open Jet (LSOJ) Testing Facility: To overcome the limitations of wind tunnel testing, the LSOJ testing facility at LSU offers a comprehensive solution. The LSOJ facility excels in bridging the gap between laboratory-scale wind tunnel experiments and full-scale outdoor testing. By utilizing a large open jet, the LSOJ facility enables testing of realistic full-scale structures while capturing intricate turbulence details, thus providing more accurate results. In the following section, we will delve into the capabilities and advantages of the LSU LSOJ facility, showcasing its pivotal role in advancing research and development in the field of wind engineering.
The combination of BLL testing and the LSOJ facility at LSU offers a powerful approach
to wind engineering research. While BLLs play a crucial role in modeling and studying
various structures, the LSOJ facility provides a more realistic representation of
turbulence and facilitates testing at full-scale. By leveraging these testing methods,
researchers can optimize cost efficiencies, enhance safety, and enable maximum design
freedom in constructing projects situated in challenging terrains or near other structures.
The LSU LSOJ facility stands as a testament to advancements in wind engineering, driving
research and development in the field to new heights.
Schematic of an open-loop wind laboratory: a fan is usually located at the exit of the test section, not to generate undesired turbulence in the flow
Schematic of a closed-loop BLL: closed-loop laboratories usually have at least two sections
Selected Publications
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Aly, A.M., Thomas, M. (2023), "Wind Induced Pressures on a Large Low-Sloped Gable Roof Building with Parapet," Architectural Science Review. https://doi.org/10.1080/00038628.2023.2174066
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Aly, A.M., Khaled, M.F., Clancy, R. (2022), "Large-Scale Open-Jet Testing: A new frontier in structural wind Engineering," Engineering Structures, 266, 1 September 2022, 114567. https://doi.org/10.1016/j.engstruct.2022.114567
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Aly, A.M., Chapain, S. (2022), "Large-Scale Open-Jet Testing for Cladding Design in High-Rise Buildings: Higher Peak Pressures Compared to Wind Tunnels," Practice Periodical on Structural Design and Construction, ASCE, 27(2). https://doi.org/10.1061/(ASCE)SC.1943-5576.0000689
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Khaled, M.F., Aly, A.M. (2022), "Assessing aerodynamic loads on low-rise buildings considering Reynolds number and turbulence effects: A review," Advances in Aerodynamics, 4(24). https://doi.org/10.1186/s42774-022-00114-0
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Aly, A.M., da Fonseca Yousef, N. (2021), "High Reynolds number aerodynamic testing of a roof with parapet," Engineering Structures 234, 1120061. https://doi.org/10.1016/j.engstruct.2021.112006
- Aly, A.M. (2014), "Atmospheric boundary-layer simulation for the built environment: past, present and future," Building and Environment, 75, 206-221.
- NASA, (2013), https://www.grc.nasa.gov, webage visited in October.
- Smeaton, J. (1759). On the Construction and Effects of Windmill Sails. The Philosophical Transactions of the Royal Society, 51.