• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.402-409
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• 2008

Wind loads and environments in realistic situations surrounded by neighboring buildings may be considerably different from those in idealized or simplified situations such as codes and standards. Interference effects of change in wind passage of a building group on wind loads and wind environments are reviewed. Wind-induced interference effects depend mainly on the building geometry and arrangement of these structures, their orientation and upstream terrain conditions. The most important factor among them may be the arrangement of building structures which can change the wind direction directly. Interference effects regarding wind loads are discussed with examples of window damages by typhoon and of pressure measurements in the boundary layer wind tunnel. Wind environment problems are also discussed, specially underlined on pedestrian comfort and safety. Various evaluation techniques or standards of wind environment are introduced. The change of wind velocity between the panel-type apartment buildings is examined, depending on the distance each other.

• Wind and Structures
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• v.4 no.5
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• pp.399-412
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• 2001

Simultaneous pressure and force measurements have been conducted on a stationary box deck section model for two configurations (namely without and with New Jersey traffic barriers) at various angles of incidence. The mean and fluctuating aerodynamic coefficients and pressure coefficients were derived, together with their spectra and with the coherence functions between the pressures and the total aerodynamic forces. The mean aerodynamic coefficients derived from force measurements are first compared with those derived from the integration of the pressures on the deck surface. Correlation between forces and local pressures are determined in order to gain insight on the wind excitation mechanism. The influence of the angle of incidence on the pressure distribution and on the fluctuating forces is also analysed. It is evidenced how particular deck section areas are more responsible for the aerodynamic excitation of the deck.

• Journal of Korean Society for Atmospheric Environment
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• v.10 no.2
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• pp.116-123
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• 1994

The E- $\varepsilon$ turbulence numerical model was applied to a flow around triangular ridge in neutral boundary layer. Scale of cavity region, mean velocity, Reynolds stress and eddy diffusivity were investigated. The height of cavity region was in satifactory agreement with the wind tunnel data while the length of cavity region was underestimated. The man wind velocities outside the cavity region were well Predicted by the model, however in cavity region the mean wind velocities of wind tunnel data were larger than the model results Reynolds stress of cavity region was overestimated by the model. The eddy diffusivity of wake region was strongly modified under the influence of triangular ridge. The local minimum of the eddy diffusivity was occured in the lee of the ridge top.

• Wind and Structures
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• v.11 no.4
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• pp.323-340
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• 2008

In this paper, the along-wind, across-wind as well as torsional dynamic wind loads on three kinds of lattice tower models are investigated using the base balance technique in a boundary layer wind tunnel. The models were specially designed, and their fundamental frequencies in the directions of the three principal axes are still in the frequency range of the spectra of wind loads on lattice towers. In order to clear contaminations to the spectra of wind loads induced by model resonance, the generalized force spectra of the first mode of the models in along-wind, across-wind and torsional directions were derived based on measured base moments of the models. The RMS generalized force coefficients are also obtained by removing the contributions of model resonance. Finally, the characteristics of the 3-D dynamic wind loads, especially those of the across-wind dynamic loads, on the three kinds of lattice towers are presented and discussed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.128-134
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• 2014

A Experimental study on frequency characteristics of the microphone array covered with Kevlar in closed test section wind tunnel. Microphones that are flush mounted in a closed test section wall of wind tunnel are subject to very high flow noise resulting from the turbulence in the wall boundary layer. At this time the microphones measure the strong hydrodynamic fluctuations generated by the flow. The phenomena are referred to a microphone self-noise and a method for reducing this has studied. In this paper the array that covered with acoustically transparent Kevlar sheet was designed and made to reduce the flow-induced self-noise. For the validation frequency characteristics of the Kevlar, the microphone array was installed on the wall and test was performed for white noise and sine wave of several frequencies using loudspeaker. In addition, the paper compared the signals as a tension of Kevlar. The results were presented that tend to decrease the sound pressure level at high frequency above 3500Hz according to existence of Kevlar.

• International Journal of High-Rise Buildings
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• v.8 no.4
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• pp.255-264
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• 2019

This paper describes large eddy simulation of wind pressures on a square cylinder in a uniform flow and a high-rise building immersed in an atmospheric turbulent boundary layer. For the atmospheric boundary layer case, the inflow turbulence is generated by a numerical wind tunnel. In the numerical simulation, particular attention is devoted to the performance of an auto hexahedral non-structural mesh. Both simulations are performed for three grid systems: an auto hexahedral non-structured grid, a structured Cartesian grid and a non-structured triangular prism grid, and for three grid numbers. The present study shows that the auto hexahedral unstructured mesh achieves the best simulation results for wind pressures on the square cylinder and the high-rise building. When the grid number is sufficiently large, the differences among the results obtained from the three investigated grid systems are not significant. However, the advantage of the auto hexahedral unstructured mesh becomes clear when the grid number decreases, because it enables a balanced distribution of orthogonal grids. The results described in this paper demonstrate that the auto hexahedral non-structured mesh has good potential applicability to simulation of urban flows.

• Wind and Structures
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• v.16 no.4
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• pp.373-391
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• 2013

This is the first of two companion papers that analyse ten years of on-site monitoring data for the Confederation Bridge to determine the validity of the original wind speeds and wind loads predicted in 1994 when the bridge was being designed. The check of the original design values is warranted because the design wind speed at the middle of Northumberland Strait was derived from data collected at shore-based weather stations, and the design wind loads were based on tests of section and full-aeroelastic models in the wind tunnel. This first paper uses wind, tilt, and acceleration monitoring data to determine the static and dynamic responses of the bridge, which are then used in the second paper to derive the static and dynamic wind loads. It is shown that the design ten-minute mean wind speed with a 100-year return period is 1.5% less than the 1994 design value, and that the bridge has been subjected to this design event once on November 7, 2001. The dynamic characteristics of the instrumented spans of the bridge including frequencies, mode shapes and damping are in good agreement with published values reported by others. The on-site monitoring data show bridge response to be that of turbulent buffeting which is consistent with the response predicted at the design stage.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.8
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• pp.1091-1096
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• 2010

This study was conducted to provide reference data for designing an alarm system that can help prevent the overturning of a container crane under wind load. Two methods, namely, fluid-structure interaction (FSI) analysis and windtunnel test, were adopted in this investigation. To evaluate the effect of wind load on the stability of the crane, a 50-ton-class container crane that is widely used in container terminals was adopted as the analysis model and 19 values were considered as design parameters for wind direction. First, the wind-tunnel test for the reduced-scale container crane model was performed according to the wind direction by using an Eiffel type atmospheric boundary-layer wind tunnel. Next, the FSI analysis for the real-scale container crane was conducted using ANSYS and CFX. Then, the uplift force determined from the FSI analysis was compared with that determined from the wind-tunnel test. Finally, a formula to compensate for the difference between the results of the FSI analysis and the wind-tunnel test was proposed.

• Wind and Structures
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• v.10 no.5
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• pp.437-462
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• 2007

A non-translating, long duration thunderstorm downburst has been simulated experimentally and numerically by modelling a spatially stationary steady flow impinging air jet. Velocity profiles were shown to compare well with an upper-bound of velocity measurements reported for full-scale microbursts. Velocity speed-up over a range of topographic features in simulated downburst flow was also tested with comparisons made to previous work in a similar flow, and also boundary layer wind tunnel experiments. It was found that the amplification measured above the crest of topographic features in simulated downburst flow was up to 35% less than that observed in boundary layer flow for all shapes tested. From the computational standpoint we conclude that the Shear Stress Transport (SST) model performs the best from amongst a range of eddy-viscosity and second moment closures tested for modelling the impinging jet flow.

• Journal of Ocean Engineering and Technology
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• v.3 no.2
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• pp.535-535
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• 1989