• Wind and Structures
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• v.6 no.2
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• pp.91-106
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• 2003

The paper presents the results of 1:50 geometrical scale laboratory modeling of wind-induced point pressure on the roof of the Texas Tech University (TTU) test building. The nominal (prevalent at the TTU site) wind and two bounding (low and high turbulence) flows were simulated in a boundary-layer wind tunnel at Colorado State University. The results showed significant increase in the pressure peak and standard deviation with an increase in the flow turbulence. It was concluded that the roof mid-plane pressure sensitivity to the turbulence intensity was the cause of the previously reported field-laboratory mismatch of the fluctuating pressure, for wind normal and $30^{\circ}$-off normal to the building ridge. In addition, it was concluded that the cornering wind mismatch in the roof corner/edge regions could not be solely attributed to the wind-azimuth-independent discrepancy between the turbulence intensity of the approach field and laboratory flows.

• Wind and Structures
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• v.3 no.4
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• pp.279-289
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• 2000

The main purpose of this paper is to demonstrate the necessity of considering wind load combinations even for low-rise buildings. It first discusses the overall quasi-static wind load effects and their combinations to be considered in structural design of low-rise buildings. It was found that the maximum torsional moment closely correlates with the maximum along-wind base shear. It was also found that the instantaneous pressure distribution causing the maximum along-wind base shear was quite similar to that causing the maximum torsional moment, and that this asymmetric pressure pattern simultaneously accompanies considerable across-wind and torsional components. Secondly, the actual wind pressure distributions causing maximum quasi-static internal forces in the structural frames are conditionally sampled and their typical pressure patterns are presented.

• Wind and Structures
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• v.35 no.5
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• pp.297-307
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• 2022

Over the past few decades, the use of wind tunnels has been increasing as a result of the rapid growth of cities and the urge to build taller and non-typical structures. While the accuracy of a wind tunnel study on a tall building requires several aspects, the precise extraction of wind pressure plays a significant role in a successful pressure test. In this research study, a low-cost expandable synchronous multi-pressure sensing system (SMPSS) was developed and validated at Ryerson University's wind tunnel (RU-WT) using electronically scanning pressure sensors for wind tunnel tests. The pressure system consists of an expandable 128 pressure sensors connected to a compact data acquisition and a host workstation. The developed system was examined and validated to be used for tall buildings by comparing mean, root mean square (RMS), and power spectral density (PSD) for the base moments coefficients with the available data from the literature. In addition, the system was examined for evaluating the mean and RMS pressure distribution on a standard low-rise building and were found to be in good agreement with the validation data.

• Wind and Structures
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• v.18 no.6
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• pp.651-668
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• 2014

Wind tunnel tests are conducted to investigate the wind loads on vertical fixed-roof cylindrical tanks with a very low aspect ratio of 0.275, which is a typical ratio for practical tanks with a volume of $100,000m^3$. Both the flat-roof tank and the dome-roof tank are investigated in present study. The first four moments of the measured wind pressure, including the mean and normalized deviation pressure, kurtosis and skewness of the pressure signal, are obtained to study the feature of the wind loads. It is shown that the wind loads are closely related to the behavior of flow around the structure. For either tank, the mean wind pressures on the cylinder are positive on the windward area and negative on the sides and the wake area, and the mean wind pressures on the whole roof are negative. The roof configurations have no considerable influence on the mean pressure distributions of cylindrical wall in general. Highly non-Gaussian feature is found in either tank. Conditional sampling technique, envelope method, and the proper orthogonal decomposition (POD) analysis are employed to investigate the characteristics of wind loads on the cylinder in more detail. It is shown that the patterns of wind pressure obtained from conditional sampling are similar to the mean pressure patterns.An instantaneous pressure coefficient can present a wide range from the maximum value to the minimum value. The quasi-steady assumption is not valid for structures considered in this paper according to the POD analysis.

• Wind and Structures
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• v.5 no.1
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• pp.25-48
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• 2002

Wind flow and pressure on the roof of the Texas Tech Experimental Building are studied along with the incident wind in an effort to understand the wind-structure interaction and the mechanisms of roof pressure generation. Two distinct flow phenomena, cornering vortices and separation bubble, are investigated. It is found for the cornering vortices that the incident wind angle that favors formation of strong vortices is bounded in a range of approximately 50 degrees symmetrical about the roof-corner bisector. Peak pressures on the roof corner are produced by wind gusts approaching at wind angles conducive to strong vortex formation. A simple analytical model is established to predict fluctuating pressure coefficients on the leading roof corner from the knowledge of the mean pressure coefficients and the incident wind. For the separation bubble situation, the mean structure of the separation bubble is established. The role of incident wind turbulence in pressure-generation mechanisms for the two flow phenomena is better understood.

• Journal of Korean Association for Spatial Structures
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• v.19 no.4
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• pp.95-102
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• 2019

In this study, the reliability of the analysis is evaluated by comparing the average wind pressure coefficient, RMS wind pressure coefficient and wind pressure spectrum with same condition of wind tunnel test which are calculated in the high-Reynolds number range of 1.2×10⁶, 2.0×10⁶ each for the typical curved shape dome structure. And it is examined by the reliability of analysis through Improved delayed detached Eddy Simulation(IDDES), which is one of the hybrid RANS/LES techniques that can analyze the realistic calculation range of high Reynolds number. As a result of the study, it was found that IDDES can be predicted very similar to the wind tunnel test. The distribution pattern of the wind pressure coefficient and wind pressure spectrum showed a similar compared with wind tunnel test.

• Wind and Structures
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• v.31 no.5
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• pp.473-482
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• 2020

The first-order method for estimating the extreme wind pressure on building envelopes with consideration of the directionality of wind speed and wind pressure is improved to enhance its computational efficiency. In this improved method, the result is obtained directly from the empirical distribution of a random selection of annual maximum wind pressure samples generated by a Monte Carlo method, rather than from the previously utilized extreme wind pressure probability distribution. A discussion of the relationship between the first- and full-order methods indicates that when extreme wind pressures in a non-typhoon climate with a high return period are estimated with consideration of directionality, using the relatively simple first-order method instead of the computationally intensive full-order method is reasonable. The validation of this reasonableness is equivalent to validating two assumptions to improve its computational efficiency: 1) The result obtained by the full-order method is conservative when the extreme wind pressure events among different sectors are independent. 2) The result obtained by the first-order method for a high return period is not significantly affected when the extreme wind speeds among the different sectors are assumed to be independent. These two assumptions are validated by examples in different regions and theoretical derivation.

• International Journal of High-Rise Buildings
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• v.11 no.4
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• pp.287-300
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• 2022

Unconventional structures are getting more popular in recent days. Large-span roofs are used for many structures, such as airports, stadiums, and conventional halls. Identifying the pressure distribution and wind load acting on those structures is essential. This paper offers a collaborative study of computational fluid dynamics (CFD) simulations and wind tunnel tests for assessing wind pressure distribution for a building with a combined slender curved roof. The hybrid turbulence model, Improved Delayed Detached Eddy Simulation (IDDES), simulates the open terrain turbulent flow field. The wind-induced local pressure coefficients on complex roof structures and the turbulent flow field around the structure were thus calculated based upon open terrain wind flow simulated with the FLUENT software. Local pressure measurements were investigated in a boundary layer wind tunnel simultaneous to the simulation to determine the pressure coefficient distributions. The results predicted by CFD were found to be consistent with the wind tunnel test results. The comparative study validated that the recommended IDDES model and the vortex method associated with CFD simulation are suitable tools for structural engineers to evaluate wind effects on long-span complex roofs and plan irregular buildings during the design stage.

• KIEAE Journal
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• v.11 no.6
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• pp.37-42
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• 2011

This Paper aims for analyzing the effect of opening types on wind-driven ventilation performance in basement parking lots of apartment. The scale model of basement parking lot was made, wind tunnel tests conducted. Wind pressure of three opening types was measured, wind pressure coefficient calculated. As the result, it showed that the air flow pattern of stack type opening was strongly changed by wind direction, but it was almost not at scuttle vent type. But, as for the difference of wind pressure coefficient, stack type opening was more than the other two types.

• Journal of Korean Association for Spatial Structures
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• v.18 no.2
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• pp.59-67
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• 2018

Various pilotis are installed in the lower part of high rise buildings. Strong winds can generate sudden airflow around the pilotis, which can cause unexpected internal airflow changes and may cause damage to the exterior of the piloti ceiling. The present study investigates the characteristics of peak wind pressure coefficient for the design of piloti ceiling exteriors by conducting wind pressure tests on high rise buildings equipped with penetration-type and end-type pilotis in urban and suburban areas. The minimum peak wind pressure coefficient for penetration-type piloti ceilings ranges from -2.0 to -3.3. Minimum peak wind pressure coefficient in urban areas was 30% larger than in suburban areas. In end-type piloti ceilings, maximum peak wind-pressure coefficient ranges from 0.5 to 1.9, and minimum peak wind-pressure coefficient ranges from -1.3 to -3.6. With changes in building height, peak wind pressure coefficient decreases as the aspect ratio increases. Peak wind-pressure coefficient increases with taller pilotis. On the other hand, when piloti height decreases, the absolute value of the minimum peak wind pressure coefficient increases.