Dissertations / Theses on the topic 'Wind speed data'

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
PROGRAMA DE EXCELENCIA ACADEMICA
A medição da velocidade de fluidos tem relevância considerável em aplicações industriais e científicas, nas quais medições com baixa incerteza são geralmente requeridas. Nesta tese, tem-se como objetivo projetar e modelar um sistema de medição de velocidade de vento utilizando fusão de dados das informações dos tempos de trânsito obtidas pelas técnicas de detecção de limiar e diferença de fase. Para este propósito, este trabalho é composto por duas partes principais. Na primeira parte, apresenta-se uma análise da propagação de incertezas das técnicas de detecção de limiar e diferença de fase considerando duas estruturas para a medição da velocidade do vento, e faz-se a comparação das faixas de medição e suas incertezas associadas para cada estrutura de medição. Na segunda parte deste trabalho, faz-se um estudo das técnicas de fusão de dados aplicadas a instrumentação e medição, identificandose duas técnicas principais baseadas em: (a) estimação de máxima probabilidade (MLE – Maximum Likelihood Estimation), (b) relação de compatibilidade fuzzy e operadores OWA (Order Weighted Average) com agregação parcial. Em seguida, estas técnicas de fusão são aplicadas para a estimação do tempo de trânsito, considerando-se várias medições independentes do tempo de trânsito obtidas pelas técnicas de detecção de limiar e diferença de fase. Finalmente, realiza-se uma análise da incerteza quantificando-se a incerteza de cada medição sobre o resultado final de fusão. Apresenta-se um estudo de caso englobando estas duas partes do trabalho, desenvolvendo-se o projeto e modelagem de um instrumento de medição de velocidade do vento com baixa incerteza, considerando-se as incertezas associadas, e o uso de técnicas adequadas de fusão de dados para prover informações com maior exatidão e confiabilidade. Resultados experimentais são realizados em um túnel de vento de baixa velocidade com o objetivo de verificar a consistência dos estudos teóricos apresentados.
Flow speed measurement has considerable relevance in industrial and scientific applications, where measurements with low uncertainty are required. In this work, a system for wind speed measurement using ultrasonic transducers is designed and modelled. This system makes use of data fusion techniques for the time-of-flight estimation, combining independent information provided by the threshold detection and phase difference methods. For this purpose, this work consists of two main parts. The first part presents an analysis of uncertainty and error propagation concerning the threshold detection and phase difference techniques and considering two structures for the wind speed measurement. Measurement ranges are associated uncertainties are then compared for each of those estrutures. In the second part of this work, data fusion techniques applied to instrumentation and measurement are studied; two main techniques are singled out: (a) Maximum Likelihood Estimation (MLE), (b) Fuzzy compatibility relation and Order Weighted Average (OWA) operators with partial aggregation. These fusion techniques are then applied to the time-of-flight estimation, by considering several independent measurements obtained through the threshold detection and phase difference techniques. Finally, uncertainty analysis is carried out by quantifying the influence of each independent measurement on the global fusion result. A case study is also presented, where an instrument for wind speed measurements with low uncertainty is designed and modelled. Appropriate techniques of data fusion aimed at improving accuracy and realiability are considered. Experiments are performed in a wind tunnel in order to verify the consistency of the results in view of the theoretical studies.

In this thesis, techniques for testing aircraft models in ground effect in a low speed wind tunnel are investigated. Although these types of tests have been done before, the current study is unique in that forces are measured with an overhead balance instead of an internal balance. This has the advantage that the types of models that are difficult to mount on a sting with an internal balance, can often be mounted with a strut protruding from the top of the model. Positioning a sting-mounted model close to the ground at a high angle-of-attack is also usually difficult if not impossible. Finally, drag measurements are often more accurate when measured with an overhead balance rather than with an internal sting-type balance. The disadvantages associated with this method of testing are identified and solutions suggested. These include accurate moment transfers and correcting for support tares and interference. The thesis also investigates general procedures associated with ground effect testing such as proper boundary corrections and the necessity of a rolling floor. A simplified preliminary test series was performed in order to identify shortcomings in the existing equipment and procedures. This series is explained in Chapter 2. Chapter 4 and 5 describe changes made to the existing equipment following this test series. These include a novel telescopic fairing to shroud the mounting strut and an internal pitching mechanism. The correction techniques and general theory are summarised in Chapter 3. The author concludes in Chapter 6 that with the application of the techniques described in this thesis, the test engineer should be able to obtain accurate and reliable data from most aircraft configurations. Additional suggestions for testing models in ground effect are also given in this chapter. Finally, a few shortcomings that still need to be investigated are mentioned at the end of Chapter 6. AFRIKAANS : Hierdie verhandeling ondersoek tegnieke om vliegtuigmodelle in grondeffek in 'n laespoed-windtonnel te toets. Alhoewel hierdie tipe van toetse al voorheen gedoen is, is die huidige studie uniek deurdat 'n oorhoofse balans eerder as 'n interne balans gebruik word. Die voordeel hiervan is dat modelle wat moeilik op 'n naald- of "sting"-balans monteer kan word, baie keer makliker monteer kan word met 'n stang wat deur die bokant van die model steek. Posisioneering van 'n naald-gemonteerde model naby aan die vloer van die tonnel by hoe invalshoeke is gewoonlik ook baie moeilik indien nie onmoontlik nie. Laastens is sleurkrag-metings wat met 'n oorhoofse balans gemeet is gewoonlik meer akkuraat as sleurkrag-metings wat met 'n interne naald-tipe balans gedoen is. Die nadele wat met hierdie toetsmetode geassosieer kan word, word geïdentifiseer en moontlike oplossing word voorgestel. Hierdie sluit die berekening in van akkurate moment-transformasies en monteersleureffekte en -steurings. Die verhandeling ondersoek ook algemene prosedures wat met grondeffektoetse geassosieer kan word, byvoorbeeld akkurate wandkorreksies en die nodigheid van die rolvloer. 'n Vereenvoudigde vooraf-toetsreeks was uitgevoer om moontlike tekortkominge in die bestaande toerusting en prosedures te identifiseer. Hierdie toetsreeks word in Hoofstuk 2 bespreek. Hoofstuk 4 en 5 verduidelik die veranderinge wat aan die bestaande toerusting gemaak is na aanleidng van hierdie toetsreeks. Hierdie veranderinge sluit 'n teleskopiese windskerm in om die monteerstang te isoleer van die wind, sowel as 'n interne heimeganisme om die invalshoek van die model te verstel. Die korreksieprosedures en algemene teorie word in Hoofstuk 3 opgesom. Die outeur se gevolgtekking in Hoofstuk 6 stel dat die toetsingenieur, met behulp van die gebruik van die tegnieke in hierdie verhandeling beskryf, in staat behoort te wees om betroubare metings te kan neem van meeste vliegtuigkonfigurasies. Verdere voorstelle vir die toets van modelle in grondeffek word ook in hierdie hoofstuk gemaak. Uiteindelik word 'n paar tekortkominge genoem wat moontlik in 'n toekomstige studie ondersoek kan word.
Dissertation (MEng)--University of Pretoria, 1999.
Mechanical and Aeronautical Engineering
unrestricted

Wind farm assessment is a costly and time consuming process when it is planned by traditional methods such as a met mast. Therefore, new models have been established and used for the wind farm assessment to ease the process of wind farm planning. These models are Global-regional models which add to cost efficiency and time saving. There are several types of these models in the market that have different accuracy. This thesis discusses and uses in simulations Global – regional model data outputs from European Centre for Medium-Range Weather Forecasts (ECMWF), Weather Research Forecast WRF and ECMWF, which is currently producing ERA-Interim, global reanalysis of the data-rich period since 1989 .The goal of the master's thesis is to see whether it is useful and efficient to use Global – regional weather model data such as the Era Interim Global Reanalysis Model data for wind assessment by comparing it with the real data series (met mast) located in Maglarp, in the south of Sweden.The comparison shows that in that specific area (hindcast) at Maglarp, in the south of Sweden, very promising results for planning a wind farm for a 100m, 120m and 38m heights.

Coastal South African cities like Port Elizabeth are said to have a strong potential for wind energy. This study aims to model wind data in order to be able assess the power potential belonging to a given site. The main challenge in modelling wind direction data is that it is categorized as circular data and therefore requires special techniques for handling that are different from usual statistical samples. Statistical tools such as descriptive measures and distribution fitting, were re-invented for directional data by researchers in this field. The von Mises distribution is a predominant distribution in circular statistics and is commonly used to describe wind directions. In this study, the circular principles described by previous researchers were developed by using the statistical software, Mathematica. Graphical methods to present the wind data were developed to give an overview of the behaviour of the winds in any given area. Data collected at Coega, an area near Port Elizabeth, South Africa, was used to illustrate the models which were established in this study. Circular distributions were fit to the directional data in order to make appropriate conclusions about the prevailing wind directions in this area.

The goal of this project is to explore how 23 different bird species respond to 3 climatic attributes. These attributes are lower than average temperatures, wind speed and precipitation level. Information about the bird species and all of the data associated with them is provided by Project FeederWatch (PFW). This is a citizen based survey study that provides key information about bird species abundance through the use of backyard and community feeders. The study volunteers from across the United States and Canada monitor these bird feeders and note important information about the species such as the number of individuals seen. Other standard information is also included such as location data and date. An original data collection pipeline was developed for this study to append climate data from Weather Underground (WU) to the PFW bird feeder data. The final dataset helped to explore how exactly the birds are reacting to winter temperatures, wind speeds and rain levels. Our results indicate that birds species in general visit the bird feeders more often as temperatures dip below average. We found that the body mass of the bird plays no role in the number of visits. Birds don't seem to be significantly affected by precipitation or wind speed as our results indicate no relationship between these climatic factors and abundance at the feeders.

碩士
清雲科技大學
電機工程研究所
95
Wind speed observations of Ching Yun University in Jhong-Li are used to investigate the wind characters inside a megalopolis. Both the graphical and maximum likelihood methods are applied to estimate the shape and the scale factors of the Weibull wind speed distribution function. It is found that the graphical method always overestimate the occurrence probability of wind speed less than 2~3m/s. Based on the obtained wind speed distribution, the related capacity factors and normalized average power are analyzed to survey the optimum parameters of wind turbine generators. Our result suggests that the wind generator can obtain the maximum efficiency when the rated wind speed is 8~11m/s.

碩士
國立海洋大學
河海工程學系碩士在職專班
90
TAIWAN is an island. Its west shores are facing TAIWAN strait Its east shores are facing pacific ocean Although TAIWAN is located within the subtropical area, however, it is relatives warm all year around. But since central mountain range is through from north to south, it becomes a natural boundary. It increases the complexity of a rapid weather change. As a result of variety of seasonal change, it creates a special weather phenomenon. Not only does it possess a typical characteristic of an island’s weather, but also its special territory shape generates a valley breeze. It impacts greatly on its atmospheric boundary layer, an evolution of mid-scale atmospheric system and its delivery of pollutants. Meteorological science is a study for the purpose of understanding a weather change in the natural world. What we hare already known, a weather change can directly impact on the economy & human life. Some bad weather can cause great damages to the human life, agricultural & industrial production. Central weather bureau prepares & announces weather forecasting daily through radio & TV broadcasting system, newspapers & other telephone system so that we can utilize weather conditions effectively. Thus, we can take advantage of preventing &overcoming unfavorable weather elements. In addition, we can enjoy life in the great nature. This is the reason why we need to pursue a continuous study of meteorological science in order to better quality life on the environment. This study utilizes wind data of nine meteorological stations of the central weather bureau. These data primarily include wind velocity & wind direction from 1951 to 2001. Wind velocity divides into extreme velocity & ordinary velocity. Extreme wind velocity is used to study the basic design wind speed & the probability distribution of wind direction for the maximum fifty years return period. Ordinary wind velocity is to analyze average wind velocity, main wind direction and its percentage of probability of relative occurrence of each wind direction. This analysis can be served as a reference for the building structural design, the selection of wind power plant location and the other application.

博士
國立臺灣科技大學
營建工程系
96
Wind speed prediction and simulation are ardent topics all the time because of its stochastic properties and significance in wind engineering. Several numerical techniques, e.g. auto-regressive moving average model, artificial intelligence technique etc., were developed for solving the related problems in recent years. In this research, a probabilistic model, named Gaussian process model, is proposed to consider the uncertainties of wind speed. Moreover, Bayesian analysis and transitional Markov Chain Monte Carlo method are employed to find the model hyper-parameters. Three examples for different issues are presented to demonstrate its practicability and satisfactory interpolation performance. Furthermore, the results also show that the various statistic properties, including exceedance probability, data correlation and distribution, of simulated wind speed are consistent with them of the training wind speed data.

碩士
淡江大學
土木工程學系碩士班
106
Taiwan is in the geographical position of multiple typhoons and earthquakes. The design of high-rise buildings must not only consider earthquake resistance, but also the impact of wind on structures. Taiwan''s current building wind resistance design specification estimates the design wind speed value based on the 10-minute average wind speed during the 50-year regression period. However, the average wind speed time used in different countries is different. There should be a constant conversion mode between different averaging time. For example, Durst Curve is used to calculate the wind speed value conversion at different averaging time. This study first used the five stations in Japan, namely Hachinohe, Tokyo, Nagoya, Osaka, and Kagoshima. The statistics were collected from the typhoon within 300 kilometers of the station from 2001 to 2007, and calculated. Each of the basic statistical characteristics of the typhoon''s mean, standard deviation, skewness, and kurtosis, and then combine the statistical characteristics of all the selected typhoons to calculate the statistical characteristics of the four regions, and use MATLAB to generate Gaussian distribution random numbers, and Using the non-Gaussian transformations proposed by Kwon and Kareem and Kanda and Lo, and the Weber simulation, a simulated extremum of the simulated typhoon is generated, which is the maximum simulated wind speed. A cumulative probability density distribution function curve is made using every hundred extreme values. Repeat one hundred sets of distribution curves and take the average line as the cumulative probability density distribution function curve representing the characteristics of this station, and observe its non-Gaussian distribution. The tail characteristics are classified into Gumbel distribution, Weibull distribution, and Frechet distribution, and the tail characteristics are discussed. Then, using the average time length in the Durst curve formula, the average wind speed conversion formula is converted into a 10-minute average time simulated wind speed and a 60-minute average time simulated wind speed converted into a 10-minute average time theoretical wind speed. The relationship between the theoretical wind speed of the 10-minute average time after the theoretical formula conversion and the simulated 10 minute average time simulated wind speed. In order to understand the influence of non-Gaussian on the average time conversion, Gaussian extremum simulations were performed for the typhoon mean wind speed values and standard deviations of each station, and compared with non-Gaussian results. The final list identifies the percentage of conversion error for different regression periods and indicates the reasons for the instability that may occur with the Durst Curve.

Thesis (M.S.)--University of Wisconsin--Madison, 1994.
Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 111-113).

Global warming, which is one of the most serious consequence of climate change, can be expected to have different effects on the atmosphere, the ocean, icebergs, etc. Global warming has also brought secondary consequences into nature and human society directly. The most negative effect among the several effects of global warming is the rising sea level related to the large typhoons which can cause flooding on low-level land, coastal invasion, sea water flow into rivers and underground water, rising river level, and fluctuation of sea tides. It is crucial to recognize surge level and its return period more accurately to prevent loss of human life and property damage caused by typhoons. This study researches two topics. The first purpose of this study is to develop a statistical model to predict the return period of the storm surge water related to typhoon Maemi, 2003 in South Korea. To estimate the return period of the typhoon, clustered separated peaks-over-threshold simulation (CSPS) has been used and Weibull distribution is used for the peak storm surge height’s fitting. The estimated return period of typhoon Maemi’s peak total water level is 389.11 years (95% confidence interval 342.27 - 476.2 years). The second aim is related to the fragility curves with the loss data caused by typhoons. Although previous studies have developed various methods to mitigate damages from typhoons, the extent of financial loss has not been investigated enough. In this research, an insurance company provides their loss data caused by the wind speed of typhoon Maemi in 2003. The loss data is very important in evaluating the extent of the damages. In this study, the damage ratio in the loss dataset has been used as the main indicator to investigate the extent of the damages. The damage ratio is calculated by dividing the direct loss by the insured amount. In addition, this study investigates the fragility curves of properties to estimate the damage from typhoon Maemi in 2003. The damage ratios and storm induced wind speeds are used as the main factor for constructing fragility curves to predict the levels of damage of the properties. The geographical information system (GIS) has been applied to produce properties’ spatial wind speeds from the typhoon. With the damage ratios, wind speeds and GIS spatial data, this study constructs the fragility curves with four different damage levels (Level I - Level IV). The findings and results of this study can be basic new references for governments, the engineering industry, and the insurance industry to develop new polices and strategies to cope with climate change.

This thesis presents the distribution of strong wind and wind pressure in the Greater Victoria area associated with winter mid-latitude cyclones based on climate data from the School-Based Weather Station Network during 6 selected days in the winters of 2006, 2007 and 2008. The objectives of this study are i) to test whether synoptic conditions favourable to severe mid-latitude cyclonic storms that are well described in the literature were associated with the selected storms, ii) to determine the time patterns of high wind speed and its direction and maximum gusts, iii) to test necessity of considering the spatial variation in air density and its controls in general assessments of the spatial variation in wind pressure and wind damage potential in the local area, iv) to identify potential areas susceptible to wind damage. Observations taken every second were from Davis Vantage Pro2 TM Plus weather stations located on the southern edge of school building roofs. Thirty-minute means and gust wind speeds were used. All six storms went north of Victoria. The synoptic conditions associated with the selected mid-latitude cyclones agreed with the ones described in literature. Strongest winds at most stations were generally from the southwest, and multiple wind speed peaks were found. The daily iii  maximum gust wind speeds were found before and/or after the highest mean wind speed peak. The spatial variation in air density and its controls were found to be negligible. Although there are a number of interacting causes of the distribution, strongest winds were at stations with smooth surrounding surfaces, close to the southern shoreline, on exposed slopes and/or near relief constrictions. The area with greatest wind speeds and damage potential was found from the east of downtown extending to Lansdowne Middle School. This study provides new knowledge of winds in the Greater Victoria area and contributes to people’s better response to wind storms, land use planning and forecasting severe windstorms.
Graduate
0368
mmatsuda@uvic.ca