scholarly journals Coaction of Wind and Rain Effects on Large-Span Hyperbolic Roofs

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Fangjin Sun ◽  
Zhonghao Xu ◽  
Daming Zhang ◽  
Yanlu Wang
Keyword(s):  
Wind Speed ◽  
Rainfall Intensity ◽  
Cfd Simulation ◽  
Pressure Coefficient ◽  
Reference Value ◽  
Average Pressure ◽  
Large Span ◽  
Roof Structure ◽  
Different Shapes ◽  
Strong Winds

Rainfall is often accompanied by strong winds. The large-span roof structure has a low height, its surrounding turbulence is high, and the wind speed changes greatly. The effects of coaction of wind and rain on the roofs cannot be ignored. Wind-driven rain (WDR) is an oblique movement phenomenon of raindrops generated by wind flow. Four types of hyperbolic roofs, that is, square, rectangular, circular, and elliptical, are selected as the objective to study the wind-driven rain by CFD simulation. Effects of wind direction, wind speed, and rainfall intensity on the WDR are analyzed. Pressure distribution of four types of hyperbolic roofs under coaction of wind and rain is obtained. The results are compared with those from the wind action only. The roofs are partitioned to obtain the coaction of wind and rain pressure of the four large-span hyperbolic roofs with different shapes under the most unfavorable working conditions. The results show that the average pressure coefficient of the roof surface increases with the increase of wind speed and rainfall intensity. The reference value of the average pressure coefficient of wind-driven rain on the surface of the roof is given, which provides a reference basis for the design of wind-driven rain on similar hyperbolic roofs.

Movement of Large Convective Rainstorms in Relation to Winds Aloft

1958 ◽  
Vol 39 (3) ◽  
pp. 129-136 ◽  
Author(s):  
C. W. Newton ◽  
Sey Katz
Keyword(s):  
Wind Speed ◽  
Wind Direction ◽  
Rainfall Data ◽  
Squall Lines ◽  
Hourly Rainfall ◽  
The Difference ◽  
Strong Winds

By means of hourly rainfall data from the Hydroclimatic Network, the motions of large rainstorms, of the kind associated with squall lines, are examined in relation to the winds aloft. Very little correlation is found between the speed of movement of the rainstorms and the wind speed at any level, although the fastest moving storms were associated with strong winds aloft. Significant correlation is found between direction of motion of rainstorms, and wind direction at 700 mb or higher levels. On the average, the rainstorms move with an appreciable component toward right of the wind direction. The difference between these results, and those from other studies based on small precipitation areas, is ascribed to propagation. The mechanism involved is discussed briefly.

Climate Conditions at Perennially Ice-Covered Lake Untersee, East Antarctica

2015 ◽  
Vol 54 (7) ◽  
pp. 1393-1412 ◽  
Author(s):  
Dale T. Andersen ◽  
Christopher P. McKay ◽  
Victor Lagun
Keyword(s):  
Wind Speed ◽  
Austral Summer ◽  
Solar Flux ◽  
East Antarctica ◽  
Daily Maximum ◽  
Mean Annual Temperature ◽  
Secondary Source ◽  
Climate Conditions ◽  
Wind Speeds ◽  
Strong Winds

AbstractIn November 2008 an automated meteorological station was established at Lake Untersee in East Antarctica, producing a 5-yr data record of meteorological conditions at the lake. This dataset includes five austral summer seasons composed of December, January, and February (DJF). The average solar flux at Lake Untersee for the four years with complete solar flux data is 99.2 ± 0.6 W m−2. The mean annual temperature at Lake Untersee was determined to be −10.6° ± 0.6°C. The annual degree-days above freezing for the five years were 9.7, 37.7, 22.4, 7.0, and 48.8, respectively, with summer (DJF) accounting for virtually all of this. For these five summers the average DJF temperatures were −3.5°, −1.9°, −2.2°, −2.6°, and −2.5°C. The maximum (minimum) temperatures were +5.3°, +7.6°, +5.7°, +4.4°, and +9.0°C (−13.8°, −12.8°, −12.9°, −13.5°, and −12.1°C). The average of the wind speed recorded was 5.4 m s−1, the maximum was 35.7 m s−1, and the average daily maximum was 15 m s−1. The wind speed was higher in the winter, averaging 6.4 m s−1. Summer winds averaged 4.7 m s−1. The dominant wind direction for strong winds is from the south for all seasons, with a secondary source of strong winds in the summer from the east-northeast. Relative humidity averages 37%; however, high values will occur with an average period of ~10 days, providing a strong indicator of the quasi-periodic passage of storms across the site. Low summer temperatures and high wind speeds create conditions at the surface of the lake ice resulting in sublimation rather than melting as the main mass-loss process.

Analysis for the Effect of Wind Barrier on Reducing Wind Velocity across a Bridge

2012 ◽  
Vol 256-259 ◽  
pp. 2739-2742
Author(s):  
Ji Hong Bi ◽  
Peng Lu ◽  
Jian Wang ◽  
Chun Bao
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Speed ◽  
Wind Velocity ◽  
Efficient Design ◽  
Wind Barrier ◽  
Strong Winds

A bridge, which is located in the route of typhoon, is considered how to assure normal traffic use against strong winds. As one of the measures, wind barrier is proposed to be set on both sides of the bridge section for reducing wind velocity across it. In this study, an analysis by using CFX, a computational fluid dynamics program, is carried out to investigate the effects of wind barrier. The speed of wind is assumed as 60m/s. To find out an efficient design of the boards, different porosity ratios(r) of the boards is assumed for comparison. The result shows that wind barrier could reduce the wind speed across the bridge effectively.

Computer Analysis of S822 Aerofoil Section for Blades of Small Wind Turbines at Low Wind Speed

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Prachi R. Prabhukhot ◽  
Aditya R. Prabhukhot
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Cfd Simulation ◽  
Maximum Velocity ◽  
Small Scale ◽  
Blade Profile ◽  
Ansys Fluent ◽  
Low Wind Speed ◽  
Upward Direction ◽  
Computational Fluid Dynamics Cfd

The power generated in wind turbine depends on wind speed and parameters of blade geometry like aerofoil shape, blade radius, chord length, pitch angle, solidity, etc. Aerofoil selection is the crucial factor in establishing the efficient wind turbine. More than one aerofoil in a blade can increase the efficiency further. Previous studies of different aerofoils have shown that efficiency of small scale wind turbine increases when NREL S822 aerofoil is used for wind speed on and above 10 m/s. This paper introduces a study on effect of low wind speed (V = 5 m/s) on performance of blade profile. Aerofoils NREL S822/S823 are used for microwind turbine with S823 near root and S822 near tip. Blade of 3 m radius with spherical tubercles over entire span is analyzed considering 5 deg angle of attack. The computational fluid dynamics (CFD) simulation was carried out using ANSYS fluent to study the behavior of blade profile at various contours. The study shows that blade experiences maximum turbulence and minimum pressure near trailing edge of the tip of blade. The region also experiences maximum velocity of the flow. These factors result in pushing the aerofoil in upward direction for starting the wind turbine to rotate at the speed as low as 5 m/s.

scholarly journals A study on wind speed correction method of lattice tower mast using CFD simulation

2018 ◽  
Vol 84 (862) ◽  
pp. 18-00042-18-00042
Author(s):  
Nobutoshi NISHIO ◽  
Shinichi INABA ◽  
Yuta YOSHIDA ◽  
Akihiro SATO ◽  
Tsuyoshi TAMUKAI ◽  
...  
Keyword(s):  
Wind Speed ◽  
Cfd Simulation ◽  
Correction Method ◽  
Lattice Tower

scholarly journals Investigation of an Innovative Rotor Modification for a Small-Scale Horizontal Axis Wind Turbine

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2649 ◽  
Author(s):  
Artur Bugała ◽  
Olga Roszyk
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Cfd Simulation ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Horizontal Axis ◽  
Power Coefficient ◽  
Small Scale ◽  
Horizontal Axis Wind Turbine ◽  
Airflow Distribution

This paper presents the results of the computational fluid dynamics (CFD) simulation of the airflow for a 300 W horizontal axis wind turbine, using additional structural elements which modify the original shape of the rotor in the form of multi-shaped bowls which change the airflow distribution. A three-dimensional CAD model of the tested wind turbine was presented, with three variants subjected to simulation: a basic wind turbine without the element that modifies the airflow distribution, a turbine with a plano-convex bowl, and a turbine with a centrally convex bowl, with the hyperbolic disappearance of convexity as the radius of the rotor increases. The momentary value of wind speed, recorded at measuring points located in the plane of wind turbine blades, demonstrated an increase when compared to the base model by 35% for the wind turbine with the plano-convex bowl, for the wind speed of 5 m/s, and 31.3% and 49% for the higher approaching wind speed, for the plano-convex bowl and centrally convex bowl, respectively. The centrally convex bowl seems to be more appropriate for higher approaching wind speeds. An increase in wind turbine efficiency, described by the power coefficient, for solutions with aerodynamic bowls was observed.

Study on a Large-Span Steel Truss Roof Isolation Bearings for Wind Load Effect Isolation Effect

2013 ◽  
Vol 405-408 ◽  
pp. 1022-1027
Author(s):  
Zi Fen Fang ◽  
Zhi Qiang Zhang ◽  
Fei Liu
Keyword(s):  
Financial Services ◽  
Base Isolation ◽  
Wind Load ◽  
Isolation Effect ◽  
Load Effect ◽  
Large Span ◽  
Roof Structure ◽  
Rubber Bearing ◽  
Steel Truss ◽  
Load Effects

The isolation of large-span Steel Truss Roof structure is developed on the basis of base isolation. The isolation of large-span Steel Truss Roof structure is to limit the transmission of wind load effect to the substructure. Based on the engineering background, we mainly discuss using rubber bearing isolation structure wind load effects. This paper will explains and demonstrates the isolation mechanism of Large-span Steel Truss Structure,and than test and verify isolation effect by Calculating through the analysis of wind tunnel tests conducted on the Yancheng financial services center, which the steel truss roof isolation bearings for wind load effect isolation effect.

Program for the Analysis of Wind-Induced Vibration of Steel Roof Structures

2011 ◽  
Vol 284-286 ◽  
pp. 517-522
Author(s):  
Wei Guo Yang ◽  
Yao Feng Wang
Keyword(s):  
Wind Pressure ◽  
Wind Loads ◽  
Frequency Domain Method ◽  
Large Span ◽  
Finite Element Software ◽  
Roof Structure ◽  
Wind Vibration ◽  
Vertical Winds ◽  
Wind Induced Vibration ◽  
Steel Roof

Wind loads are key considerations in the structural design of steel roof structures, especially for large span ones. The analysis of wind loads on large span steel roof structure (LSSRS) requires large amounts of calculations. Due to combined effects of horizontal and vertical winds, the wind induced vibrations of LSSRS are analyzed with the frequency domain method as the first application of the method for the analysis of wind responses of LSSRS. A program is developed to analyze the wind-induced vibrations due to a combination of wind vibration modes. The program, which predicts the wind vibration coefficient and wind pressure acting on the LSSRS, is designed with input and output interfaces to other finite element software, resulting in preferably solving the wind load analytical problem in the design of LSSRS. The effectiveness and accuracy of the proposed method and the program are verified by numerical analyses of practical projects.

Construction Technology of Large-Span Hybrid Structure of Suspendome with Stacked Arch in Chiping Gymnasium

2011 ◽  
Vol 243-249 ◽  
pp. 6083-6086 ◽  
Author(s):  
Xiao Bei Wang ◽  
Zhen Hua Liu ◽  
Ming Gong ◽  
Lian Fen Weng
Keyword(s):  
High Altitude ◽  
Steel Structure ◽  
Hybrid Structure ◽  
Construction Technology ◽  
Large Span ◽  
Finite Element Software ◽  
Roof Structure ◽  
Temporary Support ◽  
Stress And Deformation ◽  
Lattice Shell

Large-span hybrid structure of suspendome with stacked arch is applied into steel roof of Chiping Gymnasium. The construction of this new type structure system is difficult according to structure characteristics such as its large-span stacked arch, high installation altitude, lattice shell installation, prestressed cable tension, and tight construction period. Temporary support frame, segment lifting and high altitude splicing construction method is adopted to install the stacked arch, and total support, high-altitude spread operation method is used to install lattice dome. A spatial structural analysis is conducted on the supporting system, and the finite element software is adopted to simulate and analyze the installation process of the steel structure roof system. At the same time, stress and deformation of the roof structure are monitored by precise instruments and equipments. As the result, construction safety and quality are guaranteed.

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