| 000 -LEADER |
|---|
| fixed length control field |
04291nam a22001577a 4500 |
| 082 ## - DEWEY DECIMAL CLASSIFICATION NUMBER |
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| Classification number |
670 |
| 100 ## - MAIN ENTRY--PERSONAL NAME |
|---|
| Personal name |
Sarwar, Usama Bin Waqar |
| 245 ## - TITLE STATEMENT |
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| Title |
Impact of Turbulence Intensity on VAWT Performance in Urban Vs. Open Terrain Environments / |
| Statement of responsibility, etc. |
Usama Bin Waqar Sarwar |
| 264 ## - PRODUCTION, PUBLICATION, DISTRIBUTION, MANUFACTURE, AND COPYRIGHT NOTICE |
|---|
| Place of production, publication, distribution, manufacture |
Islamabad : |
| Name of producer, publisher, distributor, manufacturer |
SMME- NUST; |
| Date of production, publication, distribution, manufacture, or copyright notice |
2025. |
| 300 ## - PHYSICAL DESCRIPTION |
|---|
| Extent |
74p. |
| Other physical details |
Soft Copy |
| Dimensions |
30cm |
| 500 ## - GENERAL NOTE |
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| General note |
The characteristics of the incoming wind, especially the turbulence intensity (TI), greatly<br/>impact the performance of a Vertical Axis Wind Turbine (VAWTs). Vertical axis wind turbines<br/>are omnidirectional i.e. they can be directed in different directions and can be employed in<br/>highly variable flows, which makes them a very suitable candidate for complex flow<br/>environments like that of Urban landscapes. However, the impact turbulence has on the<br/>performance of VAWT still needs a lot of investigation, particularly when it comes to<br/>comparing a high turbulence intensity area like urban environments to a low turbulence<br/>intensity open area [1], [2]. The aim of the study is to examine the influence of the Turbulence<br/>Intensity on the aerodynamic behavior and the performance of a VAWT under these two<br/>contrasting environmental conditions.<br/>In order to do this, a series of Computational Fluid Dynamics (CFD) simulations were<br/>performed that involved modelling a standard VAWT that was subjected to varying inflow<br/>conditions. Turbulence intensities were varied to closely reflect a rural and urban environment.<br/>The employed approach was a time-resolved, two-dimensional (2D) Unsteady Reynolds<br/>Averaged Navier Stokes (URANS) model with a Shear Stress Transport (SST) k-ω turbulence<br/>model. The reason behind choosing this model was its ability to capture the unsteady<br/>aerodynamic phenomenon and its transient wake dynamics [3]. The key parameters that would<br/>be analyzed are Torque, power coefficient, pressure distribution, magnitude of velocity, and<br/>wake structure.<br/>The results indicate a dual role of turbulence in the performance of a VAWT. Under high TI<br/>conditions like those of an urban environment, turbulence promotes a higher degree of mixing<br/>and enhanced local vorticity near the rotor region. As a result of that, we have a higher degree<br/>of momentum transport, which acts to reenergize the boundary layer on the blades, thus<br/>delaying flow separation. Thisin turn, leads to improved torque generation at a low wind speed.<br/>This also contributes to a more effective startup behavior and reduces the turbine’s cut-in speed,<br/>which is essential for urban environments where wind is intermittent and is interrupted by the<br/>buildings, particularly skyscrapers, that act as obstructions. With an increase in turbulence<br/>intensity, the velocity magnitude contours indicate a greater degree of vortex shedding and<br/>coherent structures forming around the blade, which contributes to the turbulent mixing and<br/>energy recovery within the wake.<br/>x<br/>Contrary to that, in an open terrain, with a lower value of TI, the wind inflow remains more<br/>stable and uniform. As a result of this, the aerodynamic loading is much more predictable and<br/>the efficiency is much higher, specifically at rated wind speeds. The downside is the reduction<br/>in the turbine’s ability to harness fluctuating gusts. We see an early separation of the flow<br/>around the blade, particularly at lower rotational speeds. Wake recovery is also slower due to<br/>reduced mixing.<br/>The study thus concludes that a higher value of turbulence intensity can be beneficial for the<br/>performance of a VAWT, especially in urban environments, as it enhances flow reattachment,<br/>improves the starting behavior, and provides an increased power output under fluctuating<br/>conditions. Despite these benefits, higher turbulence intensity results in increased unsteady<br/>loading, which can impact the long-term structural integrity of the turbine. In contrast, the<br/>deployment of VAWT in an open terrain offers higher efficiency and a smoother operation, but<br/>may require a higher value of wind thresholds to initiate effective power generation. |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM |
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| Topical term or geographic name entry element |
MS Design and Manufacturing Engineering |
| 700 ## - ADDED ENTRY--PERSONAL NAME |
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| Personal name |
Supervisor : Dr. Syed Maaz Hassan |
| 856 ## - ELECTRONIC LOCATION AND ACCESS |
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| Uniform Resource Identifier |
<a href="http://10.250.8.41:8080/xmlui/handle/123456789/53777">http://10.250.8.41:8080/xmlui/handle/123456789/53777</a> |
| 942 ## - ADDED ENTRY ELEMENTS (KOHA) |
|---|
| Source of classification or shelving scheme |
|
| Koha item type |
Thesis |
