• Title/Summary/Keyword: Wind Tunnel Design

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Control Method of Wind Induced Vibration Level for High-rise buildings (초고층 건물의 풍가속도응답 조절 기법)

  • Kim Ji-Eun;Seo Ji-Hyun;Park Hyo-Seon
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2005.04a
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    • pp.375-382
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    • 2005
  • In this paper, a practical control method of wind-induced vibration of high-rise buildings is presented in the form of resizing algorithm. In the structural design process for high-rise buildings, the lateral load resisting system for the building is more often determined by serviceability design criteria including wind-induced vibration level. Even though many drift method have been developed in various forms, no practical design method for wind induced vibration has been developed so far. Structural engineers rely upon heuristic or experience in designing wind induced vibration. The performance of the proposed method is evaluated by comparing wind-induced vibration levels estimated both from approximate techniques and wind tunnel test.

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AERODYNAMIC DESIGN OF A MULTI-FUNCTION AIR DATA SENSOR BY USING CFD AND WIND TUNNEL TEST (전산해석 및 풍동시험을 이용한 다기능 대기 자료 센서의 공력 설계)

  • Park, Y.M.;Choi, I.H.;Lee, Y.G.;Kwon, K.J.;Kim, S.C.;Hwang, I.H.
    • Journal of computational fluids engineering
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    • v.15 no.3
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    • pp.32-38
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    • 2010
  • Aerodynamic design of the vane type multi-function probe was tried by using CFD and wind tunnel test for the MALE UAV and small business jets. The present multi-function probe can measure total pressure, static pressure and angle of attack by using rotating vane. Therefore, major performances are determined by aerodynamic characteristics of vane. In order to design the sensor compatible to the requirement, aerodynamic characteristics of sensors were investigated by using CFD and dynamic response analysis was also performed for transient performance. The final aerodynamic performance was measured by the wind tunnel test at Aerosonic and the results were compared with the present design. The results showed that the aerodynamic design using the CFD can be successfully used for the design of vane type multi-function air data sensor.

Equivalent static wind load estimation in wind-resistant design of single-layer reticulated shells

  • Li, Yuan-Qi;Tamura, Yukio
    • Wind and Structures
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    • v.8 no.6
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    • pp.443-454
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    • 2005
  • Wind loading is very important, even dominant in some cases, to large-span single-layer reticulated shells. At present, usually equivalent static methods based on quasi-steady assumption, as the same as the wind-resistant design of low-rise buildings, are used in the structural design. However, it is not easy to estimate a suitable equivalent static wind load so that the effects of fluctuating component of wind on the structural behaviors, especially on structural stability, can be well considered. In this paper, the effects of fluctuating component of wind load on the stability of a single-layer reticulated spherical shell model are investigated based on wind pressure distribution measured simultaneously in the wind tunnel. Several methods used to estimate the equivalent static wind load distribution for equivalent static wind-resistant design are reviewed. A new simple method from the stability point of view is presented to estimate the most unfavorable wind load distribution considering the effects of fluctuating component on the stability of shells. Finally, with comparisive analyses using different methods, the efficiency of the presented method for wind-resistant analysis of single-layer reticulated shells is established.

Experimental and Computational Investigation of Wind Flow Field on a Span Roof Structure

  • K B Rajasekarababu;G Vinayagamurthy;Ajay Kumar T M;Selvirajan S
    • 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.

Wind-induced self-excited vibrations of a twin-deck bridge and the effects of gap-width

  • Qin, X.R.;Kwok, K.C.S.;Fok, C.H.;Hitchcock, P.A.;Xu, Y.L.
    • Wind and Structures
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    • v.10 no.5
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    • pp.463-479
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    • 2007
  • A series of wind tunnel sectional model dynamic tests of a twin-deck bridge were conducted at the CLP Power Wind/Wave Tunnel Facility (WWTF) of The Hong Kong University of Science and Technology (HKUST) to investigate the effects of gap-width on the self-excited vibrations and the dynamic and aerodynamic characteristics of the bridge. Five 2.9 m long models with different gap-widths were fabricated and suspended in the wind tunnel to simulate a two-degrees-of-freedom (2DOF) bridge dynamic system, free to vibrate in both vertical and torsional directions. The mass, vertical frequency, and the torsional-to-vertical frequency ratio of the 2DOF systems were fixed to emphasize the effects of gap-width. A free-vibration test methodology was employed and the Eigensystem Realization Algorithm (ERA) was utilized to extract the eight flutter derivatives and the modal parameters from the coupled free-decay responses. The results of the zero gap-width configuration were in reasonable agreement with the theoretical values for an ideal thin flat plate in smooth flow and the published results of models with similar cross-sections, thus validating the experimental and analytical techniques utilized in this study. The methodology was further verified by the comparison between the measured and predicted free-decay responses. A comparison of results for different gap-widths revealed that variations of the gap-width mainly affect the torsional damping property, and that the configurations with greater gap-widths show a higher torsional damping ratio and hence stronger aerodynamic stability of the bridge.

Will CFD ever Replace Wind Tunnels for Building Wind Simulations?

  • Phillips, Duncan A.;Soligo, Michael J.
    • International Journal of High-Rise Buildings
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    • v.8 no.2
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    • pp.107-116
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    • 2019
  • The use of computational fluid dynamics (CFD) is becoming an increasingly popular means to model wind flows in and around buildings. The first published application of CFD to both indoor and outdoor building airflows was in the 1970's. Since then, CFD usage has expanded to include different aspects of building design. Wind tunnel testing (WTT) on buildings for wind loads goes back as far as 1908. Gustave Eiffel built a pair of wind tunnels in 1908 and 1912. Using these he published wind loads on an aircraft hangar in 1919 as cited in Hoerner (1965 - page 74). The second of these wind tunnels is still in use today for tests including building design ($Damljanovi{\acute{c}}$, 2012). The Empire State Building was tested in 1933 in smooth flow - see Baskaran (1993). The World Trade Center Twin Towers in New York City were wind tunnel tested in the mid-sixties for both wind loads, at Colorado State University (CSU) and the [US] National Physical Laboratory (NPL), as well as pedestrian level winds (PLW) at the University of Western Ontario (UWO) - Baskaran (1993). Since then, the understanding of the planetary boundary layer, recognition of the structures of turbulent wakes, instrumentation, methodologies and analysis have been continuously refined. There is a drive to replace WTT with computational methods, with the rationale that CFD is quicker, less expensive and gives more information and control to the architects. However, there is little information available to building owners and architects on the limitations of CFD for flows around buildings and communities. Hence building owners, developers, engineers and architects are not aware of the risks they incur by using CFD for different studies, traditionally conducted using wind tunnels. This paper will explain what needs to happen for CFD to replace wind tunnels. Ultimately, we anticipate the reader will come to the same conclusion that we have drawn: both WTT and CFD will continue to play important roles in building and infrastructure design. The most pressing challenge for the design and engineering community is to understand the strengths and limitations of each tool so that they can leverage and exploit the benefits that each offers while adhering to our moral and professional obligation to hold paramount the safety, health, and welfare of the public.

A Comparison of the Wind Resistance Characteristic of a Container Crane According to the Increase to the Lifting Capacity (권상용량 증가에 따른 컨테이너 크레인의 내풍특성 비교)

  • Lee, Seong-Wook;Kim, Hyung-Hoon;Han, Dong-Seop;Han, Geun-Jo;Kim, Tae-Hyung
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.204-209
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    • 2007
  • This study was carried out to analyze the effect of wind load on the structural stability of a container crane according to the increase of the lifting capacity using wind tunnel test and provided a container crane designer with data which can be used in a wind resistance design of a container crane assuming that a wind load at 75m/s wind velocity is applied on a container crane. Data acquisition conditions for this experiment were established in accordance with the similarity. The scale of a container crane dimension, wind velocity and time were chosen as 1/200, 1/13.3 and 1/15. And this experiment was implemented in an Eiffel type atmospheric boundary-layer wind tunnel with $11.52m^{2}$ cross-section area. Each directional drag and overturning moment coefficients were investigated.

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Development and Operating Test of the Supersonic Wind Tunnel with $25cm{\times}20cm$ Test Section ($25cm{\times}20cm$ 초음속 풍동 개발 및 시험 평가)

  • Kim, Sei-Hwan;Park, Ji-Hyun;Lee, Seung-Bok;Jeung, In-Seuck;Lee, Hyung-Jin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2011.11a
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    • pp.777-780
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    • 2011
  • The supersonic wind tunnel is a common facility to studies the aerodynamic phenomenon around the high speed vehicle or weapon system whose operating speed is greater than sonic speed. In this study, a design procedure and selecting the components of a new supersonic wind tunnel whose nozzle exit is $125mm{\times}100mm$ is considered. An operating test of this wind tunnel is being conducted to compare the result with the design values, mach number, etc.

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Field measurements of natural periods of vibration and structural damping of wind-excited tall residential buildings

  • Campbell, S.;Kwok, K.C.S.;Hitchcock, P.A.;Tse, K.T.;Leung, H.Y.
    • Wind and Structures
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    • v.10 no.5
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    • pp.401-420
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    • 2007
  • Field measurements of the wind-induced response of two residential reinforced concrete buildings, among the tallest in the world, have been performed during two typhoons. Natural periods and damping values have been determined and compared with other field measurements and empirical predictors. Suitable and common empirical predictors of natural period and structural damping have been obtained that describe the trend of tall, reinforced concrete buildings whose structural vibrations have been measured in the collection of studies in Hong Kong compiled by the authors. This data is especially important as the amount of information known about the dynamic parameters of buildings of these heights is limited. Effects of the variation of the natural period and damping values on the alongwind response of a tall building for serviceability-level wind conditions have been profiled using the gust response factor approach. When using this approach on these two buildings, the often overestimated natural periods and structural damping values suggested by empirical predictors tended to offset each other. Gust response factors calculated using the natural periods and structural damping values measured in the field were smaller than if calculated using design-stage values.

An Analysis of Wind Force Coefficient Distributions for Optimum Design of Single-Span Arched Greenhouse (아치형 단동온실의 최적설계를 위한 풍력계수분포도의 분석)

  • 이석건;이현우;권무남
    • Journal of Bio-Environment Control
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    • v.4 no.1
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    • pp.1-8
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    • 1995
  • One of the most destructive forces around greenhouses is wind. Wind loads can be obtained by multiplying velocity pressure by dimensionless wind force coefficient. Generally, wind force coefficients can be determined by wind tunnel experiments. The wind force coefficient distribution on a single - span arched greenhouse was estimated using experimental data and compared with reported values from various countries. The results obtained are as follows : 1. The coefficients obtained from this study agree with the values proposed by G. L. Nelson except about 0.5 of difference in the middle region of roof section. This discrepancy is mainly attributed to the dissimilarity of experimental conditions (or wind tunnel test such as Reynolds number, type of terrain, surface roughness of model, location of the lapping and measuring methods. 2. Considering that the wind force coefficients are varied along the height of a wall at wind direction perpendicular to wall, structural analysis using subdivided wind force coefficient distribution is more resonable for wall. 3. It is recommendable that wind force coefficient distribution on a roof should take more subdivision than the existing four equal divisions for more accurate structural design. 4. Structural design using wind forces close to real values is more advantageous in safety and expense.

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