Some effects of turbulence scale on the mean forces on a bluff body

Lee, B.E.

doi:10.1016/0167-6105(75)90030-6

Cited by 37 publications

(14 citation statements)

References 2 publications

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“…In addition, the lack of small-scale turbulence may lead to an underestimation of the mean response. This is in agreement with the results published in Lee [ 25 ] who found that at high values of turbulence scale, the mean drag forces on square prisms tend to have a large constant value compared to low turbulence scales. The STD and peak responses of the structure in a smooth flow are so far from those in a turbulent flow.…”

Section: Discussionsupporting

confidence: 93%

“…However, the along-wind response in the y -direction under smooth flow (SF) is relatively reduced due to the lack of high-frequency turbulence (see Figure 3(b) at 90°). It is worth noting that high-frequency turbulence in a test flow should be matching with a target real-life spectrum in order for mean wind loads to be accurately simulated in a laboratory [ 25 , 37 , 41 ]. The high-frequency turbulence (small eddies) in a test flow is a key parameter that affects the flow patterns around a bluff body, and hence mean values of loading.…”

Section: Responses Under Wind Loadsmentioning

confidence: 99%

“…Lee [ 25 ] studied the effects of turbulence scale on mean forces on square prisms. The results indicated that care must be taken when modeling a building in natural wind to ensure that ratios of turbulence scale size to building dimensions remain constant.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Turbulence, Orientation, and Site Configuration on the Response of Buildings to Extreme Wind

Aly

2014

The Scientific World Journal

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Atmospheric turbulence results from the vertical movement of air, together with flow disturbances around surface obstacles which make low- and moderate-level winds extremely irregular. Recent advancements in wind engineering have led to the construction of new facilities for testing residential homes at relatively high Reynolds numbers. However, the generation of a fully developed turbulence in these facilities is challenging. The author proposed techniques for the testing of residential buildings and architectural features in flows that lack fully developed turbulence. While these methods are effective for small structures, the extension of the approach for large and flexible structures is not possible yet. The purpose of this study is to investigate the role of turbulence in the response of tall buildings to extreme winds. In addition, the paper presents a detailed analysis to investigate the influence of upstream terrain conditions, wind direction angle (orientation), and the interference effect from the surrounding on the response of high-rise buildings. The methodology presented can be followed to help decision makers to choose among innovative solutions like aerodynamic mitigation, structural member size adjustment, and/or damping enhancement, with an objective to improve the resiliency and the serviceability of buildings.

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Section: Discussionsupporting

confidence: 93%

Section: Responses Under Wind Loadsmentioning

confidence: 99%

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Influence of Turbulence, Orientation, and Site Configuration on the Response of Buildings to Extreme Wind

Aly

2014

The Scientific World Journal

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“…However, Hoerner also states that three-dimensional bluff bodies that are not of streamline shape are relatively unaffected by the boundary layer. More recent work on the drag of buildings in ABLs (Lee, 1976;Cheng et al, 1992;Li and Melbourne, 1995;Flay and Vickery, 1995) have demonstrated that the mean drag force for many sharp-edged bluff bodies, not of streamline shape, are affected by the turbulent intensity and turbulence length scale. In general, as the turbulence intensity increases, the drag tends to be reduced because the turbulence interacts with the separated shear layer causing the wake to be reduced, yielding a more complete pressure recovery.…”

Section: Atmospheric Boundary Layer Resultsmentioning

confidence: 98%

Drag measurement and dynamic simulation of Martian wind-driven sensor platform concepts

Moody

James

et al. 2006

Journal of Fluids and Structures

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“…The effect of the integral length scale has also been studied, but it was found that its effect is much less than that of incoming wind turbulence (Haan et al , ; Li and Melbourne, ; Lee, ). Lastly, the aerodynamic behavior of a prismatic rectangular building in a boundary layer flow is similar to the two dimensional case but has many additional complexities resulting from the model end‐effects and the vertical wind speed and turbulence profiles.…”

Section: Introductionmentioning

confidence: 99%

An aerodynamic and aeroelastic experimental study on a sectional and three-dimensional rectangular tall building

Giappino

Rosa

Tomasini

et al. 2015

Struct. Design Tall Spec. Build.

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This paper examines the aerodynamic properties of a rectangular tall building with sharp edges. The building has a section aspect ratio B=D D 2:6 and a height aspect ratio H=D D 9, giving in a quite slender prismatic configuration. The study was performed on sectional and three-dimensional models of the building. The sectional model was tested in a smooth flow condition, and the aerodynamic coefficients of the section were determined. Forces and pressure distributions were measured on the three-dimensional model to compare with the aerodynamic behavior of the sectional model. Both a rigid (non-moving) and a moving model of the building were tested to analyze possible aeroelastic effects. Different levels of incoming wind turbulence were tested, since this is a key parameter in the aerodynamic behavior of the rectangular prism. Copyright or more recently, Li and Melbourne (1995) have studied the effects of the free stream turbulence on the mean pressure distribution along the separation shear layer formed on a flat plate with rectangular leading edges geometry. They showed that the main effect of the turbulence is to shorten the separation bubble, which corresponds to earlier reattachment of the separated shear layer. These alterations directly affect the pressure field on the afterbody side B, resulting in steeper mean pressure recoveries and consequently affecting the lift and drag coefficients. Flow visualization indicates that the mean reattachment position is between the peak of the mean and the peak of the standard deviation of the pressure distribution. More studies on large negative peak pressures, which are very important in wind engineering, occurring in the forward part of the separation bubble can be found in, e.g. Melbourne (1997,1989);Cherry et al. (1984).The effect of the integral length scale has also been studied, but it was found that its effect is much less than that of incoming wind turbulence (Haan et al., 1998;Li and Melbourne, 1995;Lee, 1975). Lastly, the aerodynamic behavior of a prismatic rectangular building in a boundary layer flow is similar to the two dimensional case but has many additional complexities resulting from the model end-effects and the vertical wind speed and turbulence profiles. Some studies on this have been presented, e.g. by Matsumoto et al. (1998);Surry and Djakovich (1995).Many studies considering the dynamic of the prism have also been published. In fact, the rectangular section can be subjected to vortex shedding as well as galloping oscillations. The dynamic problem is very complex, and the most significant parameters governing the system are again the elongation ratio B=D, the wind velocity V , the angle of attack of the prism˛and the level of incoming wind turbulence ( Table 1 shown the list of the main symbols).Vortex shedding generates vortex-induced vibrations (VIVs). It is a well-known phenomenon that produces narrow bandwidth fluctuating lift excitation, mainly governed by the Strouhal number St Studies on VIV can be found in, e.g. (Matsumoto, 1999;Shimada...

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Some effects of turbulence scale on the mean forces on a bluff body

Cited by 37 publications

References 2 publications

Influence of Turbulence, Orientation, and Site Configuration on the Response of Buildings to Extreme Wind

Influence of Turbulence, Orientation, and Site Configuration on the Response of Buildings to Extreme Wind

Drag measurement and dynamic simulation of Martian wind-driven sensor platform concepts

An aerodynamic and aeroelastic experimental study on a sectional and three-dimensional rectangular tall building

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