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Tytuł:
The relationship between the parameters of wind speed
Autorzy:
Halchak, V.
Syrotyuk, S.
Syrotyuk, V.
Powiązania:
https://bibliotekanauki.pl/articles/411281.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Oddział w Lublinie PAN
Tematy:
wind
wind speed
distribution function
mean values
Opis:
This paper analyzes the methods of mapping the velocity of wind flow, and using them to measure the performance of wind turbines. The dependencies of the two-parameter Weibull distribution function on the scale parameter are analyzed. It should be noted that the parameters of the distribution function, and therefore the repeatability are probabilistic. The characteristics of Rayleigh distribution for different values of the scale are presented. The analytical-expressions and peculiar velocities of the integer and half-integer values for the shape parameters reflect the relationship between the mean, mean square, average-cubic, and estimated wind-speeds. It is shown that the ratio of the square of the average speed to the standard, regardless of the values of the shape-parameters and the scale-ratio can be replaced by the corresponding G-functions.The theoretical-calculation to design the medium-speed and its relation to the current and average speeds for the Weibull distribution with a half-integer values and the shape-parameter is presented. It is proved that the recommendation considers the speed of the medium design to be proportional to the mean, and permissible only if the distribution is close to normal. It has been established that the ratio between average wind velocities (in the case of Weilbull distribution parameter) are determined only by its form and the average velocity through the scale parameter. Weibull distribution allows to facilitate and simplify their calculation methodology so as to assess the energy parameters of wind turbines.
Źródło:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes; 2015, 4, 4; 95-100
2084-5715
Pojawia się w:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Indian Ocean wind speed variability and global teleconnection patterns
Autorzy:
Sinha, M.
Jha, S.
Chakraborty, P.
Powiązania:
https://bibliotekanauki.pl/articles/2079299.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
wind speed
variability
sea surface temperature
remote sensing
Indian Ocean
Opis:
The influence of the local sea surface temperature (SST) and remote ENSO (El Niño-Southern Oscillation) indices on the wind speed (WS) data were explored for the Indian Ocean region. Relationships among the parameters were studied using spatial correlation plots and significant correlation ranges. Two months (July and January) representing opposite monsoon phases were selected for analysis for the period 1950–2016. There was a significant negative correlation between WS and SST over the Bay of Bengal (BOB) during July. Although different ENSO indices correlated differently in different areas of the Indian Ocean, the region off the coast of Sri Lanka was most significantly teleconnected. The southwest monsoon locally impacted the WS and SST relationship and the WS parameter was remotely teleconnected in both the monsoon seasons. Further empirical orthogonal function (EOF) analysis was applied on the 67 years WS data of the BOB region to extract the dominant mode representing maximum variability of the total variance. The temporal pattern of the first principal component (PC1) of WS data was linked to the North Atlantic Oscillations in January and the Atlantic Multidecadal Oscillation in July respectively. The continuous wavelet power spectra of the PC1 of WS showed significant regions in the 2–4-year band resembling the ENSO variability. Wavelet coherence applied between PC1 of WS and the ENSO indices showed greatest values for January in the 8–16-year band and for July in the 0–4-year band. A close relationship was established between the WS variability in BOB and the ENSO indices.
Źródło:
Oceanologia; 2020, 62, 2; 126-138
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Approximation and Prediction of the Wind Speed Change Function
Autorzy:
Klen, K.
Zhuikov, V.
Powiązania:
https://bibliotekanauki.pl/articles/410602.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
distributed generation
wind generator
Heisenberg’s uncertainty principle
linear approximation
Walsh functions
regression analysis
Opis:
In the article the features of energy summation from two wind generators, located at a certain distance from each other, are considered. The method of calculating the correlation function between the wind flow speed change functions in the direction of wind distribution is presented. The formulas for describing the fluctuation components of energy at the output of the wind generator are given for two cases: when the phases of the fluctuations of the wind flow on two wind generators are the same and when the fluctuations of the wind flow are in the antiphases. It is shown that to increase the energy level that can be taken from the wind power plant it is necessary to control the phase shift between the energy fluctuations at the output of the wind generators and use the energy of the storages; and to use linear approximations to approximate the wind speed change function. Under the condition of a linear change of the internal resistance of the wind generator in time, it is advisable to introduce the wind speed change function with linear approximations. The system of orthonormal linear functions based on Walsh functions is given. A table with formulas and graphs describing the first 8 functions, which are arranged in order of increasing the number of their sign alternating on the interval of functions definition, is presented. The result of the approximation of the wind speed change function with a system of 8 linear functions based on Walsh functions is shown. Decomposition coefficients, mean-square and average relative approximation errors for such approximation are calculated. In order to find the parameters of multiple linear regression the method of least squares is applied. The regression equation in matrix form is given. An example of application of linear regression prediction method to simple functions is shown. The restoration result for wind speed change function is shown. Decomposition coefficients, mean-square and average relative approximation errors for restoration of wind speed change function with linear regression method are calculated.
Źródło:
Present Problems of Power System Control; 2018, 9; 35-46
2084-2201
Pojawia się w:
Present Problems of Power System Control
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wind turbine operation parameter characteristics at a given wind speed
Autorzy:
Kamiński, Z.
Czyż, Z.
Wendeker, M.
Powiązania:
https://bibliotekanauki.pl/articles/103129.pdf
Data publikacji:
2014
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
wind turbine
renewable energy
computational fluid dynamics (CFD)
numerical analysis
Opis:
This paper discusses the results of the CFD simulation of the flow around Vertical Axis Wind Turbine rotor. The examined rotor was designed following patent application no. 402214. The turbine operation is characterised by parameters, such as opening angle of blades, power, torque, rotational velocity at a given wind velocity. Those parameters have an impact on the performance of entire assembly. The distribution of forces acting on the working surfaces in the turbine can change, depending on the angle of rotor rotation. Moreover, the resultant force derived from the force acting on the oncoming and leaving blades should be as high as possible. Accordingly, those parameters were individually simulated over time for each blade in three complete rotations. The attempts to improve the performance of the entire system resulted in a new research trend to improve the performance of working turbine rotor blades.
Źródło:
Advances in Science and Technology. Research Journal; 2014, 8, 22; 75-82
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic rating method of traction network based on wind speed prediction
Autorzy:
Su, Zhaoux
Tian, Mingxing
Sun, Lijun
Zhang, Ruopeng
Powiązania:
https://bibliotekanauki.pl/articles/2086724.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
dynamic thermal rating
IEEE-738
short-term emergency dispatch
time series model
traction power supply
wind speed prediction
Opis:
The operating temperature of the transmission line in the traction network is affected by geographical and climatic factors, especially the wind speed. To make better use of the thermal stability transmission capacity of the traction power supply system in improving the short-term emergency transmission capacity, the dynamic rating technology is introduced into the traction power supply system. According to the time-varying characteristics of the actual wind speed, a dynamic rating method of the traction network based on wind speed prediction is proposed and constructed. Based on the time series model in predicting the wind speed series along the corridor of the traction network, the temperature curve of each transmission line under different currents is calculated by combining it with the heat balance equation of an IEEE-738 capacity expansion model, thus the relationship between the peak operating temperature and current of each transmission line in the prediction period is obtained. According to the current distribution coefficient, the capacity increase limit of the traction network is determined. The example shows that the proposed dynamic rating method based on wind speed prediction is an effective method to predict the short-term safe capacity increase limit of the traction network, which can increase the comprehensive capacity of the traction network by about 45% in the next six hours, and the capacity increase effect is obvious, which can provide reference and technical support for short-term emergency dispatching of traction power supply dispatching centres.
Źródło:
Archives of Electrical Engineering; 2022, 71, 2; 379--395
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The thermal characteristics of ACCR lines as a function of wind speed – an analytical approach
Autorzy:
Zaręba, Marek
Gołębiowski, Jerzy
Powiązania:
https://bibliotekanauki.pl/articles/2173672.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wind speed
transient temperature field
steady temperature field
ACCR line
mathematical modeling
prędkość wiatru
pole temperatury stacjonarne
pole temperatury niestacjonarne
linia ACCR
modelowanie matematyczne
Opis:
The paper has investigated the effect of wind speed on selected thermal characteristics of the contemporary ACCR line. As wind speed functions, heating curves, stationary temperature profiles, steady-state current ratings and thermal time constants, have been determined. The composite core (Al–Al2O3) and the Al–Zr alloy braid were modeled as porous solids. As a result, the physical model is composed of a solid cylinder and a hollow cylinder with different material parameters of the above-mentioned elements. The mathematical model was formulated as the boundary-initial problem of the parabolic heat equation. The problem was solved by the state-superposition of and variable-separation method. On this basis, a computer program was developed in the Mathematica 10.4 environment and the velocity characteristics sought for were plotted. The results obtained analytically were positively verified by the finite-element method in the NISA v.16 environment. The physical interpretation of the determined characteristics has been given.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 3; art. no. e141006
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The application of probability density function in modeling of wind speed on the Polish Batlic Coast
Autorzy:
Czernecki, B.
Powiązania:
https://bibliotekanauki.pl/articles/108544.pdf
Data publikacji:
2014
Wydawca:
Instytut Meteorologii i Gospodarki Wodnej - Państwowy Instytut Badawczy
Tematy:
wind speed
Weibull distribution
canonical correlation analysis
statistical downscaling
Polish Baltic Coast
Opis:
The aim of the research was to identify the potential for the use of probability density functions (PDF) in modeling of near-surface wind speed. The approaches of Empirical Orthogonal Functions (EOF) and Canonical Correlation Analysis (CCA) are used in combination with 2-parametric Weibull distribution. The downscaling model was built using a diagnosed relationship between sea level pressure (SLP) patterns over Europe and the Northern Atlantic and estimated monthly values of Weibull parameters at 9 stations along the Polish Baltic Coast. The obtained scale (A) and shape (k) parameters make it possible to describe temporal variations of wind fields and their theoretical probability values. This may have further application in the modeling of extreme wind speeds for seasonal forecasting, climate prediction or in historical reconstructions. The model evaluation was done separately for the calibration (1971-2000) and validation periods (2001-2010). The scale parameter was reconstructed reasonably, while there were some problematic issues with the shape parameter, especially in the validation period. The quality of the developed models is generally higher for the winter season, due to larger SLP gradients, whereas the results for the spring and summer seasons were less satisfactory. Despite this, the 99th percentile of theoretical wind speeds are in most cases satisfactory, due to the lesser importance of the shape parameter for typical distributions in the analyzed region.
Źródło:
Meteorology Hydrology and Water Management. Research and Operational Applications; 2014, 2, 2; 23-33
2299-3835
2353-5652
Pojawia się w:
Meteorology Hydrology and Water Management. Research and Operational Applications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of the Expected Wind Speed Fluctuation on the Number of Batteries of the Balancing System
Autorzy:
Yaremenko, Mykhailo
Klen, Kateryna
Powiązania:
https://bibliotekanauki.pl/articles/2175931.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
battery
Peukert's law
optimal sizing
forecasting
Opis:
The article discusses a method of assessing the of dependence of the number of batteries that would be needed to achieve energy balance in distributed generation systems with wind turbines on ambient temperature and on the error involved in predicting the parameters of wind flow (wind speed). To describe the relationship between current rate and capacity in a given current range, Peukert’s law is used. Dependence of the Peukert's constant on ambient temperature for the lead-acid battery HZB12-180FA is calculated. Taking the lead-acid battery and wind turbine VE-2 as a reference, dependence of area of controlled operation of the battery on the wind speed forecasting error is calculated. The technique of considering ambient temperature, depth of discharge, and wind speed forecasting error when deciding the size of energy storage of the balancing system (the number of batteries and their capacity) is provided. A family of curves representing the dependence of the number of batteries constituting the balancing system on the ambient temperature and the wind speed forecasting error are presented. It is shown that as the wind speed forecasting error increases from 0% to 15% and the ambient temperature decreases from 20 °C to 20 °C, the number of batteries should be increased by approximately 2.81 times in order to maintain the same area of controlled operation of a battery.
Źródło:
Power Electronics and Drives; 2022, 7, 42; 187--196
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The characteristics of the operating parameters of the vertical axis wind turbine for the selected wind speed
Autorzy:
Kamiński, Z.
Czyż, Z.
Powiązania:
https://bibliotekanauki.pl/articles/102107.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
wind turbine
renewable energy
wind tunnel
drive torque
power
Opis:
The article presents the results of examining a wind turbine on the vertical axis of rotation. The study was conducted in an open circuit wind tunnel Gunt HM 170 in the laboratory of the Department of Thermodynamics, Fluid Mechanics and Aviation Propulsion Systems at Lublin University of Technology. The subject of research was a rotor based on the patent PL 219985, with blades capable of altering the surface of the active area (receiving kinetic energy of the wind). The study was performed on appropriately scaled and geometrically similar models maintaining, relevant to the type of research, the criterion numbers. The studied rotors with different blade inclination angles were produced using a 3D powder printer ZPrinter® 450. The results of the conducted research were obtained for the flow velocity of 6.5 m/s and three inclination angles, 30°, 60°, and 90°, at variable rotational speed. The test equipment used in the study allows maintaining the required speed, recording velocity and torque, which in turn allows an engineer to measure such characteristics of torque and power as a function of rotor speed.
Źródło:
Advances in Science and Technology. Research Journal; 2017, 11, 1; 58-65
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of the Wind Speed and the Material Emplacement on the Output Signal of PZT Piezoelectric Energy Harvester
Autorzy:
Demir, F.
Anutgan, M.
Powiązania:
https://bibliotekanauki.pl/articles/1030306.pdf
Data publikacji:
2017-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.-t
Opis:
In this study the electrical signal produced from wind energy through a (Pb_{x}X_{1-x})(Zr_{y}Ti_{z}Y_{1-y-z}) piezoelectric transducer is analyzed. The material is placed onto a metal frame at different positions and voltage outputs of each are compared at different wind flow speeds and load resistance values. The absorption of the wind energy is tested by connecting a polyurethane material in parallel and perpendicular to the wind flow direction. The use of that material with optimum emplacement condition is shown to increase the voltage output by at least two orders of magnitude, where the maximum voltage output obtained is 13 V, and the maximum power is 338 μW.
Źródło:
Acta Physica Polonica A; 2017, 131, 3; 362-365
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessment of Hazard from Damaging Wind Gusts in the Siedlce Area
Autorzy:
Radzka, Elżbieta
Olszewska, Eliza
Powiązania:
https://bibliotekanauki.pl/articles/2173241.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
wind direction
wind speed
wind gust
hazard
Opis:
The average daily values of wind speed and wind gust speed in the years 2001–2018 in Siedlce were analyzed. In the study area, the frequency of individual wind directions was determined and, according to criteria set by the Government Centre for Security, the frequency of hazards from damaging wind gusts was evaluated. The following wind gusts were considered: >20 m/s, 25 m/s and 35 m/s. It was found that, in the Siedlce area, the prevailing wind direction was west-south-westerly (WSW), and the average annual wind speed in the long-term study period was 2.99 m/s. March, April and May were the months when the highest speeds of maximum wind gusts (>35 m/s) were recorded. Extreme wind gusts the speed of which poses a hazard to the environment, national economy as well as human life and health, occurred in both the cold and warm seasons of the year.
Źródło:
Journal of Ecological Engineering; 2022, 23, 7; 192--196
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Trends Analysis of Wind in Srinagar Garhwal Valley, Uttarakhand, India
Autorzy:
Singh, Santosh
Negi, R. S.
Powiązania:
https://bibliotekanauki.pl/articles/1075718.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
AWS
Srinagar Garhwal
Wind Direction
Wind Speed
Opis:
Wind results from the air in motion. Air in motion arises from a pressure gradient. Wind direction and wind speed are two characteristics of the wind, whose inter-relationships may give us an insight into the prevailing weather condition at a particular place. This study examines the trend analysis of the wind direction and wind speed pattern of Srinagar Garhwal Valley, Uttarakhand. The average wind speed in Srinagar Valley is 2.923± 1.232 m/s. As it is seen the most frequent wind in Srinagar Garhwal has a speed from 0.50 to 2.10 m/s in the northwest direction.
Źródło:
World Scientific News; 2019, 119; 248-253
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative analysis of wind speed short term forecasts for wind farms
Porównanie modeli krótkookresowych prognoz prędkości wiatru dla siłowni wiatrowych
Autorzy:
Jaros, M.
Obidziński, P.
Powiązania:
https://bibliotekanauki.pl/articles/93819.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Inżynierii Rolniczej
Tematy:
forecasting
wind speed
wind farm
prognozowanie
prędkość wiatru
siłownia wiatrowa
Opis:
The purpose of study was verification regarding quality of wind speed forecasts used during designing the wind farm capacity, with AAN [artificial neural network] methods and Brown, Holt, Winters and ARIMA time models. Analysis included results of forecasts for December, namely a month with the biggest wind speed amplitude changes, considering data for period of 2008-2009. Analysis of results confirmed that appropriate linear models and artificial neural methods for the period of wind speed forecast may ensure good results regarding forecasts of wind power output generated by wind farms.
Celem pracy było sprawdzenie jakości prognozy prędkości wiatru, wykorzystywanej w planowaniu mocy siłowni wiatrowej, metodami SSN i modelami szeregów czasowych Browna, Holta, Wintersa i ARIMA. Porównano wyniki prognoz sporządzonych dla grudnia, miesiąca o największych zmianach amplitudy prędkości wiatru, sprawdzając je dla danych z lat 2008-2009. Analiza wyników wskazuje, że odpowiedni dobór modeli liniowych i sztucznych sieci neuronowych do horyzontu czasowego prognozy prędkości wiatru, może pozwolić na osiągnięcie dobrych wyników prognozowania energii, wytworzonej przez siłownie wiatrowe.
Źródło:
Agricultural Engineering; 2014, 18, 4; 81-90
2083-1587
Pojawia się w:
Agricultural Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zmiany prędkości wiatru w rejonie Svalbardu w latach 1948-2008
Changes in surface wind speed in Svalbard area (1948-2008)
Autorzy:
Kruszewski, G.
Powiązania:
https://bibliotekanauki.pl/articles/260657.pdf
Data publikacji:
2009
Wydawca:
Stowarzyszenie Klimatologów Polskich
Tematy:
Svalbard
analiza trendów
surface wind speed
trends analysis
Opis:
Praca charakteryzuje prędkości wiatru w oparciu o dane pochodzące z reanaliz NCEP/NCAR. Zmiany prędkości prześledzono w dwunastu punktach gridowych z rejonu Svalbardu. W przebiegu rocznym stwierdzono większe prędkości w miesiącach zimowych i mniejsze latem, przy czym amplituda tych zmian jest ponad dwukrotnie większa w południowej części rozpatrywanego obszaru. W przebiegach wieloletnich (1948-2008) obserwuje się istotny statystycznie wzrost rocznej prędkości wiatru w ośmiu gridach. W ostatnich trzy-dziestu latach wzrost ten przybierał na sile. Największe zmiany odnotowano w rejonie na północ od Svalbardu.
The aim of this work was to analyse the surface wind speed changeability in twelve grids points situated in the vicinity of Svalbard (Fig. 1) Gridded surface data from NCEP Reanalysis Derived data provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA from their Web site at http://www. cdc.noaa.gov/ were used for statistical analysis over the period 1948–2008. The highest annual wind speed values (8.0 mźs–1) were noted in the south of area (75°N), the lowest in situated over land grid [80, 20] and in the northern part of area at 82.5°N (5.9-6.0 mźs–1). During the year maximum wind speed were noted in winter months, minimum in June or July in all grid points. The differences between winter and summer values are over two times higher at 75°N than in north (82.5°N) – see Tab. 1., Fig. 2. Maximum difference (3.9 mźs–1) was noted in [75, 10], minimum (1.6 mźs–1) in [82.5, 30] grid point. Differences in wind speed between selected grid points are bigger during winter and smaller in summer. Statistically significant positive trends in annual wind speed values were found in years 1948-2008 in whole area, except at 77.5°N and [80, 20] grid point.. The trend value is the greatest in [82.5, 10] grid (+0.017 mźs–1 per year) – see Tab. 3. At latitudes 75 and 80°N values of linear trend coefficients are lower (from +0.006 to +0.01 mźs–1 per year). In shorter 30-year periods continuous significant increase in wind speed is observed at 82.5°N from 60. to the present. The highest positive trend value was noted in [82.5, 10] grid over the 1978-2008 period (+0.032 mźs–1 per year). During the last 30 years significant positive trends in wind speed are present at latitude 80°N and in grid points [77.5, 20]; [77.5, 30].
Źródło:
Problemy Klimatologii Polarnej; 2009, 19; 159-168
1234-0715
Pojawia się w:
Problemy Klimatologii Polarnej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of critical wind speed on the basis of roof blow-off
Oszacowanie krytycznej prędkości wiatru na podstawie zerwanego dachu
Autorzy:
Chmielewski, T.
Kaleta, B.
Nowak, H.
Powiązania:
https://bibliotekanauki.pl/articles/230821.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
burza wiatrowa
derecho
uszkodzenie budynku
zdmuchnięcie dachu
współczynnik aerodynamiczny
prędkość krytyczna
prędkość wiatru
wind storm
building damage
roof blow-off
aerodynamic coefficient
critical speed
wind speed
Opis:
W dniach 11-12 sierpnia 2017 r. nad Polską przeszła rozległa burza wiatrowa. Cała burza obejmowała obszar około 540 km od Wrocławia, przez Poznań, Bydgoszcz, wzdłuż Gdyni i Gdańska oraz część Wybrzeża. Z dużą siłą wiatru przeszła przez trzy województwa: Wielkopolskie, Kujawsko-Pomorskie i Pomorskie. Pomierzone prędkości wiatru osiągnęły 130 km/h, powodując duże zniszczenia na swojej drodze, a w jednej stacji synoptycznej, tj. w Elblągu prędkość wiatru przekroczyła 150 km/h. Maksymalne prędkości wiatru zostały pomierzone w następujących miejscowościach: Chojnice: 31.2 m/s (112 km/h), Gniezno: 34.8 m/s (125 km/h), Chrząstowo/Noteć: 36.0 m/s (130 km/h), Elbląg: 42,0 m/s (151 km/h). Ścieżka przejścia burzy była w przybliżeniu liną prostą, miała ponad 400 km długości i w trzech miejscach oddalonych około 70 km wiatr wiał z prędkością 100 km/, czyli burza spełniała kryteria burzy „derecho”. Burza wiatrowa spowodowała ofiary ludzkie i ogromne straty materialne opisane w pracy [8]. Celem artykułu jest oszacowanie krytycznej prędkości wiatru w zdarzeniu zerwania dachu jednopiętrowego ceglanego budynku podczas burzy wiatrowej w dniu 11 sierpnia 2017 r. W tym celu obliczono ciężar konstrukcji i pokrycia dachu oraz oszacowano siłę połączenia między murłatami i ściankami kolankowymi. Wzajemne porównanie obu tych sił umożliwiło obliczenie krytycznej prędkości wiatru, która okazała się znacznie większa od wartości pomierzonych na stacjach meteorologicznych.
Types of wind storms in Poland and examples of economic damage, threats to human life and health caused by two extreme wind events are presented. Then, a house with the roof blown-off during the derecho wind storm in Poland on August 11-12, 2017, is considered. Based on the rafter framing of the house, i.e. wooden roof structure elements and roof covered, the weight of the roof is calculated. Two cases of the strong connection between rafter plates and knee walls are estimated. With the estimation of connection strength between rafter plates and knee walls, it was possible to calculate the total force required to blow-off the roof of the house. Next, an aerodynamic force acting on the house is calculated using pressure coefficients for a low-rise house with a gable roof. The pressure coefficients were taken from the Tokyo Polytechnic University aerodynamic database. The aerodynamic force acting on the roof blown-off was calculated for a low-rise building with a gable roof for similar ratios for length, width, and height. Three wind directions, for the unknown orientation of the building, were considered, i.e. the wind direction perpendicular, parallel, and oblique to the gable wall. By comparison, the aerodynamic force with the total force required to blow-off the roof of the house, it was possible to calculate the critical wind speed needed for the roof blown-off. This wind speed is much bigger than measured by meteorological stations on the path of the derecho.
Źródło:
Archives of Civil Engineering; 2020, 66, 3; 391-405
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dependence of the surf zone aerosol on wind direction and wind speed at a coastal site on the Baltic Sea
Autorzy:
Zielinski, T.
Powiązania:
https://bibliotekanauki.pl/articles/48813.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
meteorological condition
surf zone
aerosol
coastal site
Baltic Sea
lidar
wind
Opis:
Since 1992 lidar-based measurements have been carried out under various meteorological conditions and at various times of the year. The aerosol optical properties were determined in the marine boundary layer as a function of altitude using such factors as wind direction, duration and velocity and aerosol size distribution and concentration. It was confirmed that in all cases, the total aerosol concentration, size distribution and aerosol extinction increase with wind speed but decrease with altitude. In the range of wind velocities from 1 to 15 m s−1 the mean aerosol optical thickness of the atmosphere (VIS) obtained from the lidar varied from 0.1 to 0.38 for offshore winds and from 0.01 to about 0.1 for onshore winds, while the ˚Angstr¨om parameter for VIS oscillated around 0.65 for onshore winds and around 1 for offshore winds. Both parameters depended strongly on the history of the air mass above the Baltic Sea. Such aerosol optical thicknesses are in agreement with those obtained by other researchers in the Baltic Sea area.
Źródło:
Oceanologia; 2003, 45, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measuring wind gradients in agroforestry systems by shaded piche evaporimeters. I. Validation of the square-root dependence on wind speed
Autorzy:
Kainkwa, R.M.R.
Stigter, C.J.
Powiązania:
https://bibliotekanauki.pl/articles/26056.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
anemometry
Piche evaporimeter
agriculture
agrometeorology
environment
wind reduction
agroforest system
wind gradient
Źródło:
International Agrophysics; 2000, 14, 3
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of the wind speed limits causing the break away of the vessel from jetty p in naftoport : simulation study
Autorzy:
Formela, K.
Gil, M.
Śniegocki, H.
Wilczyński, P.
Powiązania:
https://bibliotekanauki.pl/articles/244147.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
mooring
tankers
simulation
oil terminal
Naftoport
Opis:
The safety of the tanker during the loading operations carried out in the oil terminal is influenced by many factors. Based on the observations of port personnel and weather analyses in that area it was found that for Naftoport one of the most important factors affecting the security of the tanker is the wind, and more precisely – its direction and speed. Less important are accompanying waves and generated by it variable and periodic wind current. In this selected area of the Baltic Sea the direction and speed of wind change very dynamically depending on the activity of pressure patterns, which are very closely related to the occurrence of seasons. For the purpose of the article simulations were carried out of variable wind speeds, from directions causing the breakaway of the ship from the jetty, with an application of the model of the tanker in the least favourable load condition. The results obtained – the load in the mooring ropes from simulation tests were compared with the requirements of the OCIMF (Oil Companies International Marine Forum), determining the methodology of performing calculations of these forces for the selected type of tanker.
Źródło:
Journal of KONES; 2016, 23, 4; 99-108
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An assessment the wind potential energy as a generator of electrical energy in the coastal area of southern Iraq
Autorzy:
Hadi, Firas A.
Abdulsada Al-Knani, Basim
Abdulwahab, Rawnak Adel
Powiązania:
https://bibliotekanauki.pl/articles/118705.pdf
Data publikacji:
2020
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
wind energy
Basrah
wind speed analysis
wind potential
Opis:
Renewable energies have the potential to provide relatively clean energy, mostly for domestic energy. Wind power generation is expected to rise in the near future and has grown exponentially over the past decade in many countries. The most important parameter that must be taken into consideration when designing and studying wind power conversion systems is the wind speed. Probability density functions (PDF) such as Weibull is often used in wind speed and wind power analyses. This research presents an assessment of wind power based on the Weibull distribution statistics in the coastal of southern Iraq at Basrah province. Wind speed data for the study site were obtained from NASA at a height of 50 m for the period 1979–2016 with a time interval of 10 min. The data at a height of 50 m were extrapolated using the power law in order to estimate the wind speed at new heights: 30, 70 and 100 m. The different parameters of the Weibull function as well as the daily and monthly wind speeds, mean, variance and potential energy at four altitudes were estimated and analysed using Windographer software. Results indicate that the maximum wind speed at 100 m is 6.4 m·s–1, giving an average power density of 298 W·m–2, which indicates that the location of the study has marginal and useless potential for installing large wind turbines.
Źródło:
Scientific Review Engineering and Environmental Sciences; 2020, 29, 1; 37-53
1732-9353
Pojawia się w:
Scientific Review Engineering and Environmental Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characteristics of daily water temperature fluctuations in lake Kierskie (West Poland)
Autorzy:
Ptak, Mariusz
Sojka, Mariusz
Nowak, Bogumił
Powiązania:
https://bibliotekanauki.pl/articles/1051197.pdf
Data publikacji:
2019-09-30
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
lake
water temperature
air temperature
wind speed
Poznań
Opis:
The paper presents the dynamics of daily water temperature fluctuations in Lake Kierskie (West Poland) and determines the effect of air temperatures and wind speed on the variability of the parameter (water temperature). The analysis was based on hourly water temperature values from the period from May 2012 to January 2018. The data analysis permitted the description of the thermal regime of waters in the lake in the hourly cycle in reference to each month, and designation of months characterised by the highest and lowest stability of water temperatures. More than half of the analysed days was characterised by a change in water temperature not exceeding 1°C. The course of water temperature showed strongly positive correlations with air temperature, and weak correlations with wind speed. Water temperatures in the lake were correlated the strongest with air temperatures with a 24 h time step.
Źródło:
Quaestiones Geographicae; 2019, 38, 3; 41-49
0137-477X
2081-6383
Pojawia się w:
Quaestiones Geographicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative Analysis of Danger Zone Ranges Determined for LNG in the Coastal Area
Autorzy:
Kalbarczyk-Jedynak, A.
Stochła, D.
Patsch, M.
Powiązania:
https://bibliotekanauki.pl/articles/2064942.pdf
Data publikacji:
2018
Wydawca:
STE GROUP
Tematy:
danger zone ranges
LNG
wind speed
Pasquill stability
Opis:
The analysis of danger zone ranges for LNG in the coastal area is an important task on account of, inter alia, the safety of human life. It is not an easy process, which is why we consider an danger situation for various weather conditions in the function of constant wind speeds and for various wind speeds in constant weather stability. Pasquill weather stability scale and Beaufort scale with regard to terrain roughness were adopted for the analysis. Both scenarios were considered in the example of Q-flex type vessels in the Świnoujście terminal for two methods of LNG release, i.e. related to a sudden explosion and slow release caused by a leak. The analysis was conducted and considered for the values in the top and bottom flammability limit. Modelling of the danger zone range was analysed with DNV PHAST software, version 7.11. In the process of comparison of the situation related to the risk of explosion in the function of various weather stabilities according to Pasquill scale and constant wind speeds, the values of 1.5 m/s and 5 m/s were adopted, corresponding to 1 and 3 wind force on the Beaufort scale. Those speeds correspond to the water conditions featuring tiny ripples and small waves, the crests of which start to break. The adopted weather stabilities analysed for wind speed equal to 1.5 m/s are A, B, D. A-type stability signifies the least stable atmospheric conditions, and D-type means neutral conditions. In turn, for the wind speed of 5 m/s B, D and F parameters in Pasquill scale were selected. Furthermore, ranges for variable wind speed values were analysed for the selected Pasquill stability.
Źródło:
Multidisciplinary Aspects of Production Engineering; 2018, 1, 1; 829--834
2545-2827
Pojawia się w:
Multidisciplinary Aspects of Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza przepływu powietrza w złożonym układzie zabudowy pod kątem komfortu wietrznego
Wind speed analysis at pedestrian level in complex urban geometry
Autorzy:
Ruta, R.
Klemm, K.
Powiązania:
https://bibliotekanauki.pl/articles/362481.pdf
Data publikacji:
2005
Wydawca:
Instytut Fizyki Budowli Katarzyna i Piotr Klemm
Tematy:
przepływ powietrza
airflow
Opis:
W referacie przedstawione zostały wyniki analiz numerycznych przepływu, powietrza wokół budynków Wydziału Budownictwa, Architektury i Inżynierii Środowiska Politechniki Łódzkiej. Rozkład prędkości wiatru uzyskano dzięki wykorzystaniu metod symulacyjnych opartych o standardowy model turbulencyjny K -E. Szczególną uwagę zwrócono na ksztahowanie się stref przepływu wokół budynków i ich wpływ na komfort pieszych. Wyniki przedstawiono w postaci bezwymiarowej, jako stosunek prędkości w rozpatrywanym układzie (V) do prędkości w zbliżającym się przepływie (V o). Dokonano , również analizy rozkładu prędkości na poziomie pieszego w punktach najbardziej uczęszczanych przez przechodniów oraz w pobliżu wejść do budynków. W końcowej części artykułu zaproponowano rozwiązania mające na celu polepszenie warunków komfortu wietrznego przechodniów.
The paper presents the results of CFD simulation of the wind flow in a built-up area. Special attention has been paid to entrances to the buildings and the most busy pathways. The analysis of wind speed distribution has been carried out at the height of 1.8Om and were presented as the ratio of the mean wind speed V at the pedestrian height to the reference wind speed at the same height (V/Vo). Numerical simulation of wind flow has shown sofie zones in which wind comfort can be disturbed and indicated areas characterized by low wind speed and exposed to air stagnation or snow accumulation.
Źródło:
Fizyka Budowli w Teorii i Praktyce; 2005, T. 1; 296-304
1734-4891
Pojawia się w:
Fizyka Budowli w Teorii i Praktyce
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the air flow in selected buildings
Autorzy:
Bullová, I.
Powiązania:
https://bibliotekanauki.pl/articles/104898.pdf
Data publikacji:
2018
Wydawca:
Politechnika Rzeszowska im. Ignacego Łukasiewicza. Oficyna Wydawnicza
Tematy:
air flow
aerodynamic coefficient
wind speed
air exchange rate
Opis:
Airflow properties are most apparent adjacent to the surface of the building, because there take place any reactions between liquid and solid object. Air exchange rate is associated with air flow through a building by natural - through small openings and cracks in the structure. Due to leakages in the building construction, opening and closing of windows, the air in the building shifts. The value of air exchange rate is hard to predict and depend of several variables - wind speed, difference between outside and inside temperatures, the quality of the building construction. The paper analyzed the air flow in selected buildings and quantified the value of air pressure differences and the air exchange rate with the emphasis on specification of aerodynamic coefficients.
Źródło:
Czasopismo Inżynierii Lądowej, Środowiska i Architektury; 2018, 65, 1; 161-166
2300-5130
2300-8903
Pojawia się w:
Czasopismo Inżynierii Lądowej, Środowiska i Architektury
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An adaptive Kalman filter for online monitoring of mine wind speed
Adaptacyjny filtr Kalmana do ciągłego monitorowania prędkości przepływu powietrza kopalnianego
Autorzy:
Huang, De
Liu, Jian
Deng, Lijun
Li, Xuebing
Song, Ying
Powiązania:
https://bibliotekanauki.pl/articles/219283.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
prędkości przepływu powietrza kopalnianego
laserowy system Dopplerowski do rejestracji prędkości (LDV-Laser Doppler Velocimetry)
filtr Kalmana
maksymalizacja wartości oczekiwanej
układ ciągłego monitorowania
Opis:
The underground complicated testing environment and the fan operation instability cause large random errors and outliers of the wind speed signals. The outliers and large random errors result in distortion of mine wind speed monitoring, which possesses safety hazards in mine ventilation system. Application of Kalman filter in velocity monitoring can improve the accuracy of velocity measurement and eliminate the outliers. Adaptive Kalman Filter was built by automatically adjusting process noise covariance and measurement noise covariance depending on the differences between measured and expected speed signals. We analyzed the fluctuation of airflow flow using data of wind speed flow and distribution characteristics of the tunnel obtained by the Laser Doppler Velocimetry system (LDV) studies. A state-space model was built based on the tunnel airflow fluctuations and wind speed signal distribution. The adaptive Kalman Filter was calculated according to the actual measurement data and the Expectation Maximization (EM) algorithm. The adaptive Kalman filter was used to shield fluid pulsation while preserving system-induced fluctuations. Using the Kalman filter to treat offline wind speed signal acquired by LDV, the reliability of Kalman filter wind speed state model and the characteristics of adaptive Kalman Filter were investigated. Result s showed that the adaptive Kalman filter effectively eliminated the outliers and reduced the root-mean-squares error (RMSE), and the adaptive Kalman filter had better performance than the traditional Kalman filter in eliminating outliers and reducing RMSE. Field experiments in online wind speed monitoring were conducted using the optimized adaptive Kalman Filter. Results showed that adaptive Kalman filter treatment could monitor the wind speed with smaller RMSE compared with LVD monitor. The study data demonstrated that the adaptive Kalman filter is reliable and suitable for online signal processing of mine wind speed monitor.
Złożoność środowiska w którym prowadzone są pomiary prędkości powietrza w warunkach ko-palni podziemnych i niestabilność pracy wentylatorów kopalnianych mogą generować znaczne błędy losowe w rejestrowanych przebiegach sygnałów prędkości przepływu oraz powodować pojawianie się wartości oddalonych. Rejestrowane wartości oddalone oraz znaczne błędy losowe powodują wypaczenie przebiegów sygnałów rejestrowanych przez system monitorowania prędkości przepływu powietrza kopalnianego, stwarzając poważne zagrożenie dla bezpieczeństwa pracy i właściwego funkcjonowania systemu wentylacji. Zastosowanie filtru Kalmana w systemie monitorowania prędkości przepływu powietrza kopalnianego poprawia dokładność pomiarów i eliminuje występowanie wartości oddalonych. Adaptacyjny filtr Kalmana opracowano w oparciu o regulację kowariancji sygnału szumu procesowego i szumu pomiarowego w zależności od różnicy pomiędzy zmierzonymi a oczekiwanymi wartościami sygnału prędkości przepływu powietrza. Przeanalizowano wahania prędkości przepływu powietrza na podstawie charakterystyk prędkości przepływu i jej rozkładu otrzymanych z badań prowadzonych przy wykorzystaniu laserowych systemów Dopplerowskich do rejestrowania prędkości LDV (Laser Doppler Velocimetry). Zbudowano model przestrzeni stanu uwzględniający fluktuacje prędkości przepływu powietrza w tunelu oraz rozkład zarejestrowanych sygnałów prędkości przepływu powietrza kopalnianego. Obliczenia adaptacyjnego filtru Kalmana prowadzono w oparciu o bieżące dane pomiarowe, z wykorzystaniem algorytmu maksymalizacji wartości oczekiwanej (EM). Filtr adaptacyjny użyty został do wyrównania pulsacji przepływu powietrza, przy zachowaniu wszelkich zarejestrowanych fluktuacji wywołanych pracą układu. Filtr Kalmana wykorzystany został do obróbki sygnałów prędkości przepływu powietrza uzyskanych z systemu pomiaru prędkości LDV. Zbadano pewność i niezawodność modelu przestrzeni stanu prędkości przepływu powietrza uzyskanego z wykorzystaniem filtru i przeanalizowano charakterystyki adaptacyjnego filtra Kalmana. Wyniki wskazały, że zastosowanie filtru skutecznie eliminuje wartości oddalone i prowadzi do zmniejszenia wartości błędu średniokwadratowego. Wykazano także, że filtra adaptacyjny Kalmana ma wyższą skuteczność od tradycyjnych filtrów Kalmana w zakresie eliminacji wartości oddalonych i redukcji błędu średniokwadratowego. Prowadzono ciągły monitoring prędkości przepływu powietrza kopalnianego w warunkach polowych z wykorzystaniem zoptymalizowanego adaptacyjnego filtru Kalmana. Zarejestrowane wyniki wskazują, że zastosowanie filtra adaptacyjnego do obróbki sygnału prędkości przepływu prowadzi do uzyskania niższych wartości błędu średniokwadratowego niż w systemach monitoringu LVD. Zebrane w trakcie badań wyniki wykazały pewność i skuteczność działania filtra adaptacyjnego przy jego zastosowaniu do ciągłego monitorowania prędkości przepływu powietrza w kopalniach.
Źródło:
Archives of Mining Sciences; 2019, 64, 4; 813-827
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zmiany składowej strefowej prędkości wiatru (U-wind) na wschód od Svalbardu (1981-2005)
The changes of zonal wind speed component (U-wind) east of Svalbard area (1981-2005)
Autorzy:
Kruszewski, G.
Powiązania:
https://bibliotekanauki.pl/articles/260777.pdf
Data publikacji:
2007
Wydawca:
Stowarzyszenie Klimatologów Polskich
Tematy:
składowa strefowa prędkości wiatru (U-wind)
temperatura powietrza
Svalbard
zonal wind speed component (U-wind)
air temperature
Opis:
Praca charakteryzuje składową strefową prędkości wiatru w trzech gridach usytuowanych po wschodniej stronie Svalbardu oraz jej związki z temperaturą powietrza na stacjach zachodniego wybrzeża Spits-bergenu. W rejonie położonym na wschód od archipelagu obserwuje się dominację cyrkulacji wschodniej, której natężenie wyraźnie wzrasta przy przemieszczaniu się na południe. W przebiegu rocznym stwierdzono nasilanie się cyrkulacji wschodniej w miesiącach zimowych i osłabianie latem, przy czym zmienność wartości U-wind w mie-siącach chłodnej pory roku jest największa. Przewaga cyrkulacji zachodniej zaznacza się latem przez okres od jednego (na 75°N) do pięciu miesięcy (na 80°N), a jej natężenie rośnie wraz z szerokością geograficzną.
The study presents variability of zonal wind speed (U-wind) in three grids 2.5x2.5° situated in the vicinity of the eastern coast of Svalbard in period 1981–2005. Gridded surface data from NCEP Reanalysis Derived data provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA from their Web site at http://www.cdc.noaa.gov/ were used for statistical analysis. In analysed area negative values of U-wind are typical. Annual average eastern air-flow is much stronger in the south (–1.54 m/s in grid [75, 30]) than in north (–0.31 m/s in grid [80, 30]) – see fig. 1 and 2. The biggest interannual changeability of U-wind values is also observed in lower latitudes. Significant decreasing trends were found in annual U-wind values in grid points [80, 30] (–0.05 m/s by year) and [77.5, 30] (–0.04 m/s by year). During the year eastern air-flow reach the maximum in winter months. In summer time easterly circulation is weaker. Positive U-wind values (western air-flow) prevails in July (grid [75, 30]); June, July and August (grid [77.5, 30]) and from May to September in grid [80, 30]. Intensity of western air-flow increase with latitude too. The biggest changeability in monthly U-wind values in all grid points was observed in February. Decreasing trends in monthly U-wind values were found in [80, 30] grid in February (–0.13 m/s by year) and in [77.5, 30] grid in March and May (–0.11 and –0.08 m/s by year). Correlations between U-wind and zonal westerly circulation index W values for Spitsbergen area (given by Niedźwiedź, 2006) are strong for all grids and seasons, but the strongest were noted in grid [75, 30] – linear correlation coefficient from r = +0.75 (winter) to r = +0.87 (summer) – see fig. 5. Some relations between U-wind and monthly air temperature in Svalbard-Lufthavn and Ny Alesund were noticed too (fig. 6). The strongest negative correlations were found in July, May and April.
Źródło:
Problemy Klimatologii Polarnej; 2007, 17; 77-85
1234-0715
Pojawia się w:
Problemy Klimatologii Polarnej
Dostawca treści:
Biblioteka Nauki
Artykuł
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