Wind Pressure and Wind-Induced Vibration of Heliostat

2008 ◽  
Vol 400-402 ◽  
pp. 935-940 ◽  
Author(s):  
Ying Ge Wang ◽  
Zheng Nong Li ◽  
Bo Gong ◽  
Qiu Sheng Li
Keyword(s):  
Dynamic Response ◽  
Wind Direction ◽  
Wind Load ◽  
Wind Pressure ◽  
Induced Response ◽  
Vertical Angle ◽  
Lateral Direction ◽  
Direction Angle ◽  
Wind Pressures ◽  
Fluctuating Wind

Heliostat is the key part of Solar Tower power station, which requires extremely high accuracy in use. But it’s sensitive to gust because of its light structure, so effect of wind load should be taken into account in design. Since structure of heliostat is unusual and different from common ones, experimental investigation on rigid heliostat model using technology of surface pressure mensuration to test 3-dimensional wind loads in wind tunnel was conducted. The paper illustrates distribution and characteristics of reflector’s mean and fluctuating wind pressure while wind direction angle varied from 0° to 180° and vertical angle varied from 0° to 90°. Moreover, a finite element model was constructed to perform calculation on wind-induced dynamic response. The results show that the wind load power spectral change rulers are influenced by longitudinal wind turbulence and vortex and are related with Strouhal number; the fluctuating wind pressures between face and back mainly appear positive correlation, and the correlation coefficients at longitudinal wind direction are smaller than those at lateral direction; the fluctuating wind pressures preferably agree with Gaussian distribution at smaller vertical angle and wind direction angle. The wind-induced response and its spectrums reveal that: when vertical angle is small, the background responsive values of reflector’s different parts are approximately similar; in addition, multi-phased resonant response occurring at the bottom. With the increase of , airflow separates at the near side and reunites at the other, as produces vortex which enhances dynamic response at the upper part.

Wind Loading and Wind Effects on the Roof of Harbin West Railway Station

2010 ◽  
Vol 163-167 ◽  
pp. 4280-4285
Author(s):  
Di Wu ◽  
Ying Sun ◽  
Yue Wu
Keyword(s):  
Wind Tunnel ◽  
Linear Time ◽  
Time History ◽  
Wind Load ◽  
Wind Pressure ◽  
Wind Loading ◽  
Induced Response ◽  
Railway Station ◽  
History Analysis ◽  
Fluctuating Wind

Taking Harbin west railway station as the researching object, the wind load distribution as well as its effects, which are widely used in practice, is investigated. First, wind pressure distribution on a rigid model is measured simultaneously in a wind tunnel. Some special characteristics of the measured wind pressure, especially its fluctuating component, are discussed. Then the fluctuating wind pressure field is reconstructed based on the synchronous multi-pressure scanning technique of wind tunnel tests and the proper orthogonal decomposition (POD) technique. The influence of lower RC structure on wind-induced vibration is investigated using non-linear time-history analysis. At last, a new method is introduced to obtain equivalent static wind load (ESWL) that reproduce all largest load effects at the same time. With the synthetic application of above methods, the problems such as: complex time and spatial distribution of fluctuating wind; multi-mode vibration of wind-induced response; multiple equivalent objectives for ESWL, can be solved efficiently.

Correlation and Combination Factors of Wind Forces on Cylindrical Roof Structures

2017 ◽  
Vol 17 (09) ◽  
pp. 1750104 ◽  
Author(s):  
Bo Chen ◽  
Pengpeng Zhong ◽  
Weihua Cheng ◽  
Xinzhong Chen ◽  
Qingshan Yang
Keyword(s):  
Side Wall ◽  
Single Layer ◽  
Correlation Coefficients ◽  
Wind Load ◽  
Wind Pressure ◽  
Wind Loads ◽  
Horizontal Wind ◽  
Parameter Study ◽  
Response Component ◽  
Wind Pressures

The correlations among wind pressures on roof and walls are examined for the cylindrical roof buildings with different rise-span ratios based on wind tunnel data. Wind-induced dynamic response is also analyzed with a parametric study concerning span length, rise-span ratio, stiffness of supporting frames and connection type between roof and supporting frames, where the roof system is a single-layer cylindrical reticular shell. For both roof and supporting frames, the responses induced by vertical wind loads on the roof and by horizontal wind loads on the walls are investigated. The correlation coefficients of these response components are examined. The results showed that the fluctuating wind pressure on the roof is strongly correlated with the wind pressure on the side wall and the leeward wall, but weakly correlated with the wind pressure on the windward wall. The response of roof and supporting frames caused by the wind loads on the roof is much larger than that of wind loads on the walls. On the bases of a comprehensive parameter study and complete quadratic combination (CQC) rule, a practical simplified combination rule is suggested for estimating response of roof and supporting frames. It is given as sum of response component caused by wind load on roof and that of wind load on walls multiplied with a combination factor of [Formula: see text].

Rise Steel Wind-Induced Response Analysis

2014 ◽  
Vol 1006-1007 ◽  
pp. 56-60
Author(s):  
Ya Nan Hu ◽  
Qing Xu ◽  
Guo Qiang Wu
Keyword(s):  
Shear Deformation ◽  
Dynamic Characteristics ◽  
Response Curve ◽  
Time History ◽  
Wind Load ◽  
Induced Response ◽  
Response Analysis ◽  
Response Curves ◽  
Pressure Time ◽  
Fluctuating Wind

Taking a rise steel as a study, study response of the structure to the dynamic characteristics under fluctuating wind load. The results showed that: deformation of structure under the fluctuating wind load is shear deformation; Structural displacement response curve is similar to the curve of the pressure time history. Because of consider different heights the structure of spatial correlation affect, Displacement positions on different floors response curves are differ.

scholarly journals Influence of Longitudinal Fin Tubes Arrangement in LNG Ambient Air Vaporizers on the Wind Load

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 405
Author(s):  
Filip Lisowski ◽  
Edward Lisowski
Keyword(s):  
Wind Direction ◽  
Ambient Air ◽  
Wind Load ◽  
Wind Pressure ◽  
Strength Analysis ◽  
Important Data ◽  
Finned Tubes ◽  
Average Wind ◽  
Computational Fluid Dynamics Cfd ◽  
Fin Tubes

The article presents the results of computational fluid dynamics (CFD) analysis of the wind action on liquefied natural gas (LNG) ambient air vaporizers (AAVs). A study concerning AAV with a 6 × 6 tubes array is presented to demonstrate how the distribution of longitudinal finned tubes and wind direction affect the average load and wind pressure acting on the vaporizer structure. The main goal of the study is to estimate the wind load on the structure and wind pressure on individual tubes depending on the pitch of the tubes arrangement. The above parameters are crucial for the strength analysis of the vaporizer structure. The derived analysis results provide important data on the variation of pressure on individual tubes, wind velocity inside AVV structure and indicate a significant increase in the average wind load acting on the structure for a wind direction of 45 degrees compared to a perpendicular direction.

Wind Load Characteristics of a Long-Span Retractable Roof Structure

2014 ◽  
Vol 525 ◽  
pp. 397-402
Author(s):  
Jian Guo Zhang ◽  
Hui Min Zhuang
Keyword(s):  
Wind Direction ◽  
Small Area ◽  
Wind Tunnel Test ◽  
Wind Load ◽  
Coastal City ◽  
Long Span ◽  
Roof Structure ◽  
Rigid Model ◽  
Load Characteristics ◽  
Fluctuating Wind

Taking a long-span retractable roof structure, which locates in a coastal city of China, as an example, a wind tunnel test on a rigid model was carried out. This paper analyzes the wind load characteristics of this structure under three conditions: open, closed and closed with damage in small area of windows. The block shape coefficients as well as its variation with wind direction are given; meanwhile, this paper analyzes the fluctuation characteristics of wind load, obtaining the gust coefficient as well as the variation of fluctuation coefficients with wind direction, which can be applied to the design of coating members in this structure. By comparing the analysis results under three conditions, the following conclusion can be reached: the long-span structure is more resistant against mean wind load when the roof is open than when it is closed. There is no decrease in fluctuating wind load and in some wind directions; the fluctuating wind load will be even larger. Additionally, the damage in small area of windows does not much affect the wind load characteristics on structure.

Wind Tunnel Test of Tall Buildings with Irregularities of Elevation

2014 ◽  
Vol 578-579 ◽  
pp. 1208-1211
Author(s):  
Jian Guo Zhang ◽  
Hui Min Zhuang
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Tall Buildings ◽  
Wind Pressure ◽  
High Rise ◽  
Pressure Distributions ◽  
Building Models ◽  
The Mean ◽  
Wind Pressures ◽  
Fluctuating Wind

In this paper, 2 high-rise building models with ladder and cascade irregularities of elevation were tested in a wind tunnel respectively to measure the mean and fluctuating wind pressure distributions. The mean and RMS (root-mean-square) coefficients of the drag, lift and torsion moment on the measuring layer were obtained from the wind pressures. In the direction which the buildings were positive in the wind, the variation of these above mentioned coefficients with height and the power spectrum densities of the fluctuating wind loads on sudden changed positions were analyzed in detail. Compared with the elevation regular tall building, the wind load characteristics of irregular ones were more complicated.

Research on the Characteristics of Wind Load on L-Shape High-Rising Building

2014 ◽  
Vol 501-504 ◽  
pp. 925-931 ◽  
Author(s):  
Jian Guo Zhang ◽  
Hui Min Zhuang
Keyword(s):  
Wind Tunnel ◽  
Frequency Domain ◽  
Wind Direction ◽  
Current Practice ◽  
Pressure Measurements ◽  
Current Load ◽  
Research Results ◽  
The Mean ◽  
Wind Pressures ◽  
Fluctuating Wind

The mean and fluctuating wind pressures on an L-shape high-rising building were obtained through simultaneous pressure measurements in a wind tunnel. The shape coefficients on each surface and their variations with wind direction are investigated, which are more detailed than current load codes. Considering that there may be two composition forms, namely integrated-type and separated-type, when an L-shape high-rising building is structurally designed, the amplitude and frequency-domain characteristics of the base moment in along wind, across wind and torsion direction of the above two types are presented respectively. The research results show that the change regularities of shape coefficients on each surface with wind direction are different from each other and current practice using the shape coefficients of a certain wind direction to structurally design is worth discussing; the characteristics of three directions base moments on an integrated-type L-shape high-rising building are rather complicated and those on a separated-type building appear as obvious interfering effects.

scholarly journals Dynamic Response Analyses of Plastic Greenhouse Structure considering Fluctuating Wind Load

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yingchun Jiang ◽  
Yikui Bai ◽  
Cong Wang ◽  
Yonggang Wang ◽  
Xinfu Pang
Keyword(s):  
Dynamic Response ◽  
Timoshenko Beam ◽  
Maximum Stress ◽  
Beam Theory ◽  
Wind Load ◽  
Timoshenko Beam Theory ◽  
Fluctuating Wind ◽  
Node Displacement ◽  
Dangerous Section ◽  
Skeleton Structure

Wind load is one of the main factors of plastic greenhouse collapse. To solve the dynamic response problem of greenhouses under wind load and determine the dangerous section of a skeleton structure, the investigated lump method is presented for the dynamic response analysis of a plastic greenhouse, considering pulsating wind on the basis of Timoshenko beam theory. First, the investigated lump is designed according to the Timoshenko beam microbody concept. On the basis of Timoshenko beam theory, the governing equations of the skeleton structure of the greenhouse are derived, and the realization process of the algorithm is also provided. Second, the accuracy and effectiveness of the proposed numerical method are verified by an example in which the bending wave of a variable cross section beam with free ends propagates. Finally, the dynamic response of the steel skeletons of plastic greenhouses is analyzed under the effect of the simulation wind speed, and the spatial distribution of the maximum node displacement and the section maximum stress of the steel skeleton are obtained. Computational results show that the displacement peak is near the top of the plastic greenhouse. The most dangerous section of the top chord in the steel skeleton is near the leeward bottom, which has a maximum stress of 219.4 MPa, and the most dangerous section of the bottom chord is near the 1 m height on the leeward side of the plastic greenhouse, which has a maximum stress of 248.5 MPa. Bending stress is the main factor of the rapid increase of stress at the bottom of the skeleton. The maximum node displacement and cross-sectional stress caused by fluctuating wind loads are higher than those caused by average wind loads. The fluctuating wind load should be considered in the wind-induced response analyses of plastic greenhouses.

scholarly journals Steady Wind Load on External Surface and Its Effect on Wind-Induced Response for a 200 m High Natural-Draught Cooling Tower

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Yunfeng Zou ◽  
Fanrong Xue ◽  
Xuhui He ◽  
Chenzhi Cai ◽  
Shouke Li
Keyword(s):  
Pressure Distribution ◽  
Wind Profile ◽  
Cooling Tower ◽  
Pressure Coefficient ◽  
Wind Load ◽  
External Pressure ◽  
Wind Pressure ◽  
Induced Response ◽  
Simplified Approach ◽  
Static Responses

Wind tunnel tests were carried out to measure the wind pressure of a 200 m high natural-draught cooling tower. An analysis of the distribution characteristics of external pressure was then conducted to determine the pressure coefficients Cp(θ, z) in a given wind profile. Finally, the effect on the response of the shell and the buckling safety of the shell, applying the simplified height-constant pressure coefficient Cp(θ) and the realistic pressure Cp(θ, z), was determined. Taking the wind load specified in the code as an example, the influence of the distribution of external pressure on the wind-induced response was further analyzed. The results indicate that the pressure distribution varies with not only the height z but also the circumferential angle θ, and the wind load of both ends of the tower is significantly greater than that of its middle. Moreover, the wind-induced static responses of the tower under the action of the realistic pressure distribution Cp(θ, z) and the simplified approach Cp(θ) are basically consistent, because the wind load distribution is more important than its magnitude for the wind-induced response of cooling tower, and the wind-induced response of the cooling tower is dominated by the local shell deformation.

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