scholarly journals INFLUENCE OF SPATIAL ORIENTATION OF FRAME BUILDINGS ON METAL CAPACITY OF STEEL COLUMNS

2021 ◽  
pp. 56-63
Author(s):  
V.A. Pashynskyi ◽  
Keyword(s):  
Wind Direction ◽  
Spatial Orientation ◽  
Wind Pressure ◽  
Total Load ◽  
Steel Columns ◽  
North East ◽  
Frame Buildings ◽  
Steel Consumption ◽  
Statistical Justification ◽  
Characteristic Values

Abstract. The calculated values of wind pressure are identified without taking into account changes in wind speed and pressure from different directions. Current load standards in Ukraine allow taking into account the decreasing coefficients of wind direction if there is sufficient statistical justification and when the objects are located on open flat terrain. The purpose of this work is to identify possible effect of considering the orientation of frame buildings and corresponding coefficients of the wind direction when designing steel columns of one-story frame buildings. By analyzing design and calculated parameters of one-story industrial and civil buildings, possible limits of their change were established, and a plan for the experimental design of columns from broad-flanged rolling H-beams was developed and implemented. A dependence was obtained and described by analytical expression that allow forecasting steel consumption for the columns of single-aisle one-story buildings, taking into account their height, total load from roof and active component of wind pressure. Based on the results of earlier studies, the characteristic values of wind pressure and generalized wind direction coefficients were established for each of 25 regions of Ukraine. For most part of the territory of Ukraine, minimum wind loads are realized when wind directions are north-south or north-east-south-west. Generalized wind direction coefficients, together with the formula for the forecasting mass of columns, made it possible to identify possible savings in steel on the columns of one-story buildings taking into account spatial orientation of buildings. On average, throughout the territory of Ukraine, metal consumption of rolling columns decreases by 4.2%, and in some cases, depending on the region, wind direction and building height, it can decrease to 17.5%. Significant influence of the underlying surface and surrounding buildings on the nature of the wind flow allows wind direction coefficients to be taken into account only when calculating the frames of buildings located in an open flat area, under conditions that their values are statistically substantiated using the results of wind observations at nearest meteorological stations.

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.

scholarly journals Evaluating Performance of Utilizing Onshore Wind Turbines Specifically the Farm Turbines in Kuwait

2019 ◽  
Vol 7 (1) ◽  
pp. 31-48
Author(s):  
Mohammed Salem Alsubai'e ◽  
Saad Abdullah Alshatti
Keyword(s):  
Renewable Energy ◽  
Wind Speed ◽  
Wind Turbines ◽  
Wind Direction ◽  
Onshore Wind ◽  
North East ◽  
The North ◽  
Proportional Relation ◽  
Proper Design ◽  
The Impact

Renewable energy is considered one of the most important and clean sources; since it does not produce any type of emission or pollution. In Kuwait, the energy of wind is existing in three main locations, which are; Ras Jal Aliyah, Bubian in addition to Subiyah, where the characteristics of wind have been evaluated in this paper based on the data generated from the meteorological measurements at 10m height. Also, different studies have been performed in this paper in order to analyze the impact of height on the parameters of wind energy, wind density, in addition to wind speed. Jal Aliyah location has been studied in this paper and the results showed that there is a proportional relation between the wind speed and power, where the maximum power is potential if the speed is equal to 29.1 m/s, and the maximum averaged flux of wind power is equal to 725.54 W/m2. Where both Bubidan Island and Ras Subiyah showed the wind direction in the North-East quadrant with speed is greater than 10 m/s. But, the higher polarized distribution of Jal Aliyah was in the north direction. Based on the obtained results, it can be concluded that this paper provides and suggests a proper design of the wind turbines for designers.

scholarly journals Evaluation of whitefly population and weather effect of cassava mosaic incidence on commonly grown cassava in Benue State, Nigeria

2020 ◽  
Vol 24 (10) ◽  
pp. 1839-1846
Author(s):  
I Time ◽  
E Okoroafor ◽  
J.O. Nwogwugwu ◽  
A.A. Batcho
Keyword(s):  
Wind Speed ◽  
Wind Direction ◽  
Disease Incidence ◽  
Natural Infection ◽  
Block Design ◽  
Mosaic Disease ◽  
Cassava Mosaic Disease ◽  
Whitefly Population ◽  
North East ◽  
Vector Population

Vector population and weather are critical in virus disease incidence and could be strategic for its management in agriculture. To investigate the influence of whitefly population and weather on Cassava Mosaic Disease (CMD) in cassava, TMS 419 and TME 30572, commonly grown in the state were planted. The varieties were laid out in Randomized Complete Block Design in four replicates and left to natural infection by CMD viruses. At two weeks after planting and fortnightly, whitefly population counts were taken, CMD incidence was estimated and severity scored on 5- point scale. Daily temperature, humidity, wind speed and wind direction were obtained as secondary data. Data were analysed using ANOVA at p=0.05. Whitefly population (18/plant) was significant (P≤0.05) in the first 30 days at 26.9-27.1oC, 42% humidity, 10 Km/hr wind speed and when the wind direction was in the East or North-East. The vector population then declined until the end of experiment. Cassava mosaic incidence changed with whitefly population, humidity and wind speed. Disease incidence in cassava plots was low (3.6%). TME30572 maintained lower disease incidence (3.0%) and severity (2.0) during the study. R2 indicated that 27, 42 and 57% of whitefly population could be explained by temperature, humidity and wind speed, respectively while 4% of the disease incidence could be explained by the whitefly population. The number of CMD infected plants peaked (4%) when population of whitefly was 18/plant, above which the disease reduced at 0.0017 rate per unit change in the vector population. Mosaic disease incidence in cassava plots was influenced by vector population as conditioned by the weather. Keywords: Bemisia tabaci, Cassava, Cassava Mosaic Disease, Nigeria, Weather, Whitefly vector

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.

scholarly journals Analysis of Wind Speed and Wind Pressure on the Facades in Frequency Domain for the Modelling of Air Change Rate

2020 ◽  
Vol 172 ◽  
pp. 09005
Author(s):  
Krystyna Pietrzyk
Keyword(s):  
Wind Speed ◽  
Frequency Domain ◽  
Wind Direction ◽  
High Frequency ◽  
Pressure Coefficient ◽  
Building Envelope ◽  
Wind Pressure ◽  
Change Rate ◽  
Air Change Rate ◽  
Air Exchange

Air exchange in buildings is driven by pressure difference across the building envelope caused by wind and difference in density between external and internal air. The evaluation of the influence of wind on the air change rate is usually limited to the analysis of the hourly mean wind speed. Wind is a random phenomenon characterized by the broad energy spectrum. The high frequency part can be responsible for the oscillation of the air through the openings resulting in the increased air exchange. Wind pressure coefficient on the leeward site mostly depends on the form characteristics of the object in relation to wind direction. The analysis of wind speed and wind pressure on the facades in frequency domain can deliver interesting data to air change rate model. Some of the results of continuous measurements carried out on a single-family house for 8 months are presented in frequency domain. The statistics of wind speed, wind direction and pressure differences across the 6 building components are calculated. The wind turbulence and the pressure fluctuations on the facades and the roof of the building are being investigated using energy spectra of their signals. Farther analysis of the experimental results is needed to be able to include high frequency wind in the infiltration model.

Cross-section strength of concrete-filled HSS columns at simple beam connections

1987 ◽  
Vol 14 (3) ◽  
pp. 408-417 ◽  
Author(s):  
E. Dunberry ◽  
D. Leblanc ◽  
R. G. Redwood
Keyword(s):  
Cross Section ◽  
Axial Load ◽  
Strength Reduction ◽  
Column Length ◽  
Small Reduction ◽  
Total Load ◽  
Steel Columns ◽  
Tubular Columns ◽  
Stub Columns ◽  
Empirical Means

Tests are described in which short, rectangular steel columns filled with concrete are loaded to failure under axial load. Part of the load is applied at typical beam connections within the column length; and part is applied at the top, representing the load from upper stories of a building. The length of the column near the connection over which slip takes place is examined, and the ultimate strength of the columns is compared with that of stub columns loaded uniformly over their length. A small reduction in strength is found to occur, which depends upon the proportion of total load applied at the connection. An empirical means of accounting for this strength reduction is given. Key words: columns, composite construction, connections, tubular columns, axial compression.

Comparison of numerical methods in estimating Weibull parameters to install a sustainable wind farm in mount Bamboutos, Cameroon

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Marinette Jeutho Gouajio ◽  
Pascalin Tiam Kapen ◽  
David Yemele
Keyword(s):  
Numerical Methods ◽  
Wind Power ◽  
Power Density ◽  
Wind Direction ◽  
Wind Farm ◽  
Content Type ◽  
Frequency Distributions ◽  
Weibull Parameters ◽  
Wind Power Density ◽  
North East

Purpose The purpose of this paper is to evaluate the wind energy potential of Mount Bamboutos in Cameroon by comparing nine numerical methods in determining Weibull parameters for the installation of a sustainable wind farm. Design/methodology/approach By using statistical analysis, the analysis of shape and scale parameters, the estimation of the available wind power density and wind direction frequency distributions, the objective of this paper is to compare nine numerical methods in estimating Weibull parameters for the installation of a sustainable wind farm in Mount Bamboutos, Cameroon. Findings The results suggested that the minimum and maximum values of the standard deviation occurred in the months of May and November 2016, respectively. The graphical method appeared to be the most effective method with the maximum value of variance and minimum values of chi-square and RMSE. The scale factor parameter values indicated that Mount Bamboutos hills were a potential site for electricity generation. The analysis of wind power density showed that it reached the maximum and minimum values in February and September, respectively. The wind direction frequency distributions showed that the prevailing wind directions were North-East. Originality/value The wind energy potential of Mount Bamboutos in Cameroon was performed by using nine numerical methods. Therefore, it could be effective to have a prediction model for the wind speed profile. The analysis of wind power density showed that it reached the maximum and minimum values in February and September, respectively. The wind direction frequency distributions showed that the prevailing wind directions were North-East.

Synoptic forcing of wind and temperature in a large cirque 300 km from the coast of East Antarctica

1995 ◽  
Vol 7 (4) ◽  
pp. 409-420 ◽  
Author(s):  
Stig Jonsson
Keyword(s):  
Wind Speed ◽  
Air Temperature ◽  
Wind Direction ◽  
Large Scale ◽  
Weddell Sea ◽  
Air Pressure ◽  
Small Scale ◽  
Katabatic Winds ◽  
North East ◽  
Synoptic Forcing

Between 18 January 1988 and 3 June 1989, an automatic weather station recorded 13 different weather parameters every 3 h on a blue-ice area located in Scharffenbergbotnen, a large cirque in central Heimefrontfjella 300 km from the Weddell Sea coast. The first part of the paper reports on annual and monthly data regarding air temperature, air pressure, wind speed and wind direction, and a comparison is also made with corresponding data from the Neumayer and Halley stations. The second part deals mainly with winter (i.e. April–September) conditions in Scharffenbergbotnen. They seem, at least during 1988–89, to have been characterized by a large-scale (30–40 days) and, superimposed on the large-scale, a small-scale (3–4 days) co-variation of air temperature, air pressure and wind speed. The large-scale variation was earlier found to be synoptically forced. This paper shows that synoptic forcing exists also on smaller time scales. Pools of cold, stagnant air are regularly formed in the cirque only to be blown away by katabatic winds triggered by small variations in the synoptic pressure field. When this happens the air temperature increases by more than 20°C and the wind direction swings from east towards south-east. When low pressures dominate in the eastern part of the Weddell Sea, the katabatic winds become very strong, but weaker wind pulses also take place when the synoptic pressure gradient is directed towards the north-east. It therefore seems as if these very regular katabatic events are forced both by synoptic-scale pressure gradients and gradients due to the sloped inversion.

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