scholarly journals Wind Loads on Single-span Plastic Greenhouses and Solar Greenhouses

2013 ◽  
Vol 23 (5) ◽  
pp. 622-628 ◽  
Author(s):  
Zai Q. Yang ◽  
Yong X. Li ◽  
Xiao P. Xue ◽  
Chuan R. Huang ◽  
Bo Zhang
Keyword(s):  
Wind Tunnel ◽  
Wind Direction ◽  
Pressure Coefficient ◽  
Wind Pressure ◽  
Pressure Coefficients ◽  
Wind Speeds ◽  
Direction Angle ◽  
Transparent Surface ◽  
Solar Greenhouse ◽  
Wind Pressure Coefficient

Wind tunnel tests were conducted in an NH-2-type wind tunnel to investigate the wind pressure coefficients and their distribution on the surfaces of a single-span plastic greenhouse and a solar greenhouse. Wind pressures at numerous points on the surfaces of the greenhouse models were simultaneously measured for various wind directions. The critical wind speeds, at which damage occurred on the surfaces of single-span plastic greenhouses and solar greenhouses, were derived. To clearly describe the wind pressure distribution on various surface zones of the greenhouses, the end surface and top surface of the plastic greenhouse and the transparent surface of the solar greenhouse were divided into nine zones, which were denoted as Zone I to Zone IX. The results were as follows: 1) At wind direction angles of 0° and 45°, the end surface of the single-span plastic greenhouse was on the windward side, and the maximum positive wind pressure coefficient was near 1. At wind direction angles of 90° and 180°, the entire end surface of the single-span plastic greenhouse was on the leeward side, and the maximum negative wind pressure coefficient was near −1. The maximum positive wind pressure on the end surface of the single-span plastic greenhouse appeared in Zone IV at a wind direction angle of 15°, whereas the maximum negative pressure appeared in Zone VIII at a wind direction angle of 105°. 2) Most of the wind pressure coefficients on the top surface of the plastic greenhouse were negative. The maximum positive and negative wind pressure coefficient on the top surface of the plastic greenhouse occurred in Zones I and II, respectively, at a wind direction angle of 60°. 3) At a wind direction angle of 0°, the distribution of wind pressure coefficient contours was steady in the middle and lower zones of the transparent surface of the solar greenhouse, and the wind pressure coefficients were positive. At a wind direction angle of 90°, the wind pressure coefficients were negative on the transparent surface of the solar greenhouse. A maximum positive wind pressure coefficient was attained at a wind direction angle of 30° in Zone IX, whereas the maximum suction force occurred in Zone VII at a wind direction angle of 135°. 4) The minimum critical wind speeds required to impair the single-span plastic greenhouse and solar greenhouse were 14.5 and 18.9 m·s−1, respectively.

scholarly journals Influence of the near standing hall for wind flowing around group of circular cylinders

2020 ◽  
Vol 310 ◽  
pp. 00013 ◽  
Author(s):  
Ivana Veghova ◽  
Olga Hubova
Keyword(s):  
Wind Tunnel ◽  
Pressure Distribution ◽  
Pressure Coefficient ◽  
Wind Pressure ◽  
Circular Cylinders ◽  
Wind Flow ◽  
Force Coefficient ◽  
Turbulent Wind ◽  
Wind Speeds ◽  
Wind Pressure Coefficient

This article deals with experimental investigation of air flow around in – line standing circular cylinders and influence of nearby standing hall on external wind pressure distribution. The wind pressure distribution on the structures is an important parameter in terms of wind load calculation. For vertical circular cylinders in a row arrangement only wind force coefficient is possible find in Eurocode. 1991-1-4. External wind pressure coefficient depends on wind direction and the ratio of distance and diameter b. Influence of nearby standing structure is not possible find in Eurocode. The series of parametric wind tunnel studies was carried out in Boundary Layer Wind Tunnel (BLWT) STU to investigate the external wind pressure coefficient in turbulent wind flow. Experimental measurements were performed in BLWT for 2 reference wind speeds, which fulfilled flow similarity of prototype and model. We have compared the results of free in - line standing 3 circular cylinder and influence of hall on distribution of wind pressure at 3 height levels in turbulent wind flow and these results were compared with values in EN 1991-1-4.

scholarly journals Wind Pressure Coefficients Zoning Method Based on an Unsupervised Learning Algorithm

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Danyu Li ◽  
Bin Liu ◽  
Yongfeng Cheng
Keyword(s):  
Wind Tunnel ◽  
Unsupervised Learning ◽  
Wind Direction ◽  
Learning Algorithm ◽  
Pressure Coefficient ◽  
Wind Tunnel Test ◽  
Wind Pressure ◽  
Roof Structure ◽  
Validity Indices ◽  
Wind Pressure Coefficient

Damage of the cladding structures usually occurs from the wind-sensitive part, which can cause the damaged conditions to obviously vary from different areas especially on a large roof surface. It is necessary to design optimization due to the difference of wind loads by defining more accurate wind pressure coefficient (WPC) zones according to the wind vulnerability analysis. The existing wind pressure coefficient zoning methods (WPCZM) have successfully been used to characterize the simple roof shapes. But the solutions for the complex and irregular roof shapes generally rely on the empirical judgment which is defective to the wind loading analysis. In this study, a classification concept for WPC values on the roof surface is presented based on the unsupervised learning algorithm, which is not limited by the roof geometry and can realize the multitype WPC zoning more accurately. As a typical unsupervised learning algorithm, an improved K-means clustering is proposed to develop a new WPCZM to verify the above concept. And a method to determine the optimal K-value is presented by using the K-means clustering test and clustering validity indices to overcome the difficulty of obtaining the cluster number in the traditional methods. As an example, the most unfavorable pressure and suction WPC zones are studied on a flat roof structure with single wind direction and full wind direction based on the data obtained from the wind tunnel test. As another example, the mean pressure coefficient zones are studied on a saddle roof structure under 0- and 45-degree wind direction based on the data obtained by the wind tunnel test. And the proposed WPCZM is illustrated and verified.

CFD Modeling of Pressure Coefficients for a Natural Ventilation Study in an Experimental Low Rise Building

2013 ◽  
Author(s):  
Robel Kiflemariam ◽  
Cheng-Xian Lin
Keyword(s):  
Natural Ventilation ◽  
Pressure Coefficient ◽  
Wind Pressure ◽  
Analytical Models ◽  
Cfd Modeling ◽  
Engineering Practice ◽  
Pressure Coefficients ◽  
Wind Pressure Coefficient ◽  
Detailed Assessment ◽  
Ventilation Rates

Mean wind pressure coefficient (Cp) is one of the major input data for natural ventilation study using building energy simulation approach. Due to their importance, they need to be accurately determined. In current engineering practice, tables and analytical Cp models only give mostly averaged results for simpler models and configurations. Considering the limitation of tables and analytical models, Computational Fluid Dynamics (CFD) could provide a means for an accurate and detailed assessment of Cp. In this paper, we make use of a relatively high resolution, detailed experiments done at Florida Intentional University to validate a CFD modeling of the pressure coefficients Cp. The results show that existing CFD model has a good agreement with experimental results and gives important information of distribution of Cp values over the surface. The local values of the Cp are investigated. In addition, the CFD derived Cp and discharge coefficient (Cd) values are utilized in semi-analytical ventilation models in order to get a more accurate value of ventilation rates.

Wind Load Characteristics of Tall Building with Atrium

2013 ◽  
Vol 639-640 ◽  
pp. 515-522
Author(s):  
Yong Gui Li ◽  
Q.S. Li
Keyword(s):  
Wind Tunnel ◽  
Critical Role ◽  
Pressure Coefficient ◽  
Tall Building ◽  
Wind Pressure ◽  
Wind Loads ◽  
Design Guideline ◽  
Pressure Coefficients ◽  
Opening Ratio ◽  
Wind Pressures

Wind tunnel test of 1:500 rigid model of tall building with atrium was carried out. Based on the experimental results, characteristics of wind pressures on atrium facades and wind loads on the structure were investigated in detail. The results show that the formation of flow separation on the building top plays a critical role in the generation of wind pressures on the atrium facades. Meanwhile, wind pressure coefficient distributions on the atrium facades are found to be relatively uniform. Moreover, the horizontal and vertical correlations of pressure coefficient exhibit high at most locations on atrium facades. With the increasing of the opening ratio, the mean wind pressure coefficients first decreased and then stabilized, and the fluctuating wind pressure coefficients first decreased and then increased. A design guideline for the wind-resistant design of atrium facades was proposed, and the results predicted by the proposed guideline were in good agreement with those from the wind tunnel tests, indicating that the proposed guideline can be used in engineering applications. When the opening ratio is no more than 5.33%, the effect of the facade pressures within the atrium on the wind loads on the structure can be ignored. For such cases, the wind-resistant design for a tall building with atrium can refer to that of a similar shape tall building without atrium.

scholarly journals Experimental Study on the Effects of Aspect Ratio on the Wind Pressure Coefficient of Piloti Buildings

2021 ◽  
Vol 13 (9) ◽  
pp. 5206
Author(s):  
Jangyoul You ◽  
Changhee Lee
Keyword(s):  
Wind Direction ◽  
Urban Areas ◽  
Pressure Coefficient ◽  
Experimental System ◽  
Outer Edge ◽  
Urban Environments ◽  
Wind Pressure ◽  
Maximum Peak ◽  
Suburban Areas ◽  
Wind Pressure Coefficient

Owing to strong winds during the typhoon season, damage to pilotis in the form of dropout of the exterior materials occurs frequently. Pilotis placed at the end exhibit a large peak wind pressure coefficient of the ceiling. In this study, the experimental wind direction angle of wind pressure tests was conducted in seven directions, with wind test angles varying from 0° to 90° at intervals of 15°, centered on the piloti position, which was accomplished using the wind tunnel experimental system. Regardless of the height of the building, the maximum peak wind pressure coefficient was observed at the center of the piloti, whereas the minimum peak wind pressure coefficient was noted at the corners, which corresponds with the wind direction inside the piloti. The distribution of the peak wind pressure coefficient was similar for both suburban and urban environments. However, in urban areas, the maximum peak wind pressure coefficient was approximately 1.4–1.7 times greater than that in suburban areas. The maximum peak wind pressure coefficient of the piloti ceiling was observed at the inside corner, whereas the minimum peak wind pressure coefficient was noted at the outer edge of the ceiling. As the height of the building increased, the maximum peak wind pressure coefficient decreased. Suburban and urban areas exhibited similar peak wind pressure distributions; however, the maximum peak wind pressure coefficient in urban areas was approximately 1.2–1.5 times larger than that in suburban areas.

Experimental Study on the Four Pipes Self-Supporting Steel Chimney

2013 ◽  
Vol 805-806 ◽  
pp. 1413-1415
Author(s):  
Zi Hou Yuan ◽  
Yi Chen Yuan ◽  
Wei Sun
Keyword(s):  
Pressure Coefficient ◽  
The Body ◽  
Wind Pressure ◽  
Test Results ◽  
Wind Speeds ◽  
Coefficient Distribution ◽  
Average Wind ◽  
Extreme Wind ◽  
Wind Pressure Coefficient ◽  
Rigid Model

In the first test segment (12m×16m) of 8m×6m wind tunnel with simulation of atmospheric boundary layer, we did first measuring pressure test research on rigid model of four tube self-supporting steel chimney, and got average wind pressure coefficient, maximum and minimum wind pressure coefficient distribution, as well as wind loads body coefficient of this structure, thus gave the body coefficient and extreme wind load envelopes of two species height chimney. The results show that in two wind speeds, the test results have good coincidence, reasonable value, and good regularity.

Determination of the Average Wind Pressure of Circular Flat and Saddle Roof Building Based on the Numerical Wind Tunnel Method

2012 ◽  
Vol 204-208 ◽  
pp. 865-868
Author(s):  
Cai Hua Wang ◽  
Hui Jian Li ◽  
Jian Feng Wu
Keyword(s):  
Wind Tunnel ◽  
Low Cost ◽  
Pressure Coefficient ◽  
Simple Algorithm ◽  
Wind Pressure ◽  
Building Structures ◽  
Class D ◽  
Average Wind ◽  
Wind Pressure Coefficient ◽  
Numerical Wind Tunnel Method

For numerical wind tunnel method has the advantages of low cost, fast speed, the more comprehensive results, the paper using CFD knowledge and the FLUENT software, using RSM turbulence model, SIMPLE algorithm, simulation class D landform, to have numerical simulation of average wind pressure coefficient for of the circular planar and saddle roof building ,which the current code for the design of building structures did not give, to provide reference for determining the average wind pressure coefficient of the circular planar and saddle roof building .

Sign in / Sign up

Export Citation Format

Share Document