Relevant bibliographies by topics / Wind shear

Contents

  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Academic literature on the topic 'Wind shear'

Author: Grafiati
Published: 4 June 2021
Last updated: 29 July 2024

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Journal articles on the topic "Wind shear"

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Kim, Hyeon-Gi, Byeong-Min Kim, Jin-Han Kim, In-Su Paek, and Neung-Soo Yoo. "Prediction of Wind Shear Exponent in Complex Terrain." Journal of the Korean Solar Energy Society 32, no. 2 (April 30, 2012): 87–94. http://dx.doi.org/10.7836/kses.2012.32.2.087.

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Goodrich, Robert K., Corrinne S. Morse, Larry B. Cornman, and Stephen A. Cohn. "A Horizontal Wind and Wind Confidence Algorithm for Doppler Wind Profilers." Journal of Atmospheric and Oceanic Technology 19, no. 3 (March 1, 2002): 257–73. http://dx.doi.org/10.1175/1520-0426-19.3.257.

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Abstract Boundary layer wind profilers are increasingly being used in applications that require high-quality, rapidly updated winds. An example of this type of application is an airport wind hazard warning system. Wind shear can be a hazard to flight operations and is also associated with the production of turbulence. A method for calculating wind and wind shear using a linear wind field assumption is presented. This method, applied to four- or five-beam profilers, allows for the explicit accounting of the measurable shear terms. An error analysis demonstrates why some shears are more readily estimated than others, and the expected magnitudes of the variance for the wind and wind shear estimates are given. A method for computing a quality control index, or confidence, for the calculated wind is also presented. This confidence calculation is based on an assessment of the validity of the assumptions made in the calculations. Confidence values can be used as a quality control metric for the calculated wind and can also be used in generating a confidence-weighted average wind value from the rapid update values. Results are presented that show that errors in the wind estimates are reduced after removing values with low confidence. The wind and confidence methods are implemented in the NCAR Wind and Confidence Algorithm (NWCA), and have been used with the NCAR Improved Moments Algorithm (NIMA) method for calculating moments and associated moment confidence from Doppler spectra. However, NWCA may be used with any moment algorithm that also computes a first moment confidence. For example, a very simple confidence algorithm can be defined in terms of the signal-to-noise ratio.
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Long, Chi, Tao Yu, Jian Zhang, Xiangxiang Yan, Na Yang, Jin Wang, Chunliang Xia, Yu Liang, and Hailun Ye. "Sub-Hourly Variations of Wind Shear in the Mesosphere-Lower Thermosphere as Observed by the China Meteor Radar Chain." Remote Sensing 16, no. 7 (April 6, 2024): 1291. http://dx.doi.org/10.3390/rs16071291.

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Wind shear has important implications for Kelvin–Helmholtz instability (KHI) and gravity waves (GWs) in the mesosphere–lower thermosphere (MLT) region where its momentum transport process is dominated by short-period (<1 h) GWs. However, the sub-hourly variation in wind shear is still not well quantified. This study aims to improve current understanding of vertical wind shear by analyzing multi-year meteor radar measurements at the Mohe (MH, 53.5°N, 122.3°E), Beijing (BJ, 40.3°N, 116.2°E), Wuhan (WH, 30.5°N, 114.6°E), and Fuke (FK, 19.5°N, 109.1°E) stations in China. The wind field is estimated by a new algorithm, e.g., the damped least squares fitting. Taking the wind shear estimated by normal products as a criterion, the shear produced by the new algorithm has more statistical convergence as compared to the traditional algorithm, e.g., the least squares fitting. Therefore, we argue that the 10 min DLSA wind probably produces a more reasonable vertical shear. Both intensive wind shears and GW kinetic energy can be simultaneously captured during the 0600–1600 UTs of May at MH and during the 1300–2400 UTs of March at FK, possibly implying that the up-propagation of GWs could contribute to the production of large wind shears. The sub-hourly variation in wind shears is potentially valuable for understanding the interrelationship between shear (or KHI) and GWs.
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Markowski, Paul, and Yvette Richardson. "On the Classification of Vertical Wind Shear as Directional Shear versus Speed Shear." Weather and Forecasting 21, no. 2 (April 1, 2006): 242–47. http://dx.doi.org/10.1175/waf897.1.

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Abstract Vertical wind shear is commonly classified as “directional” or “speed” shear. In this note, these classifications are reviewed and their relevance discussed with respect to the dynamics of convective storms. In the absence of surface drag, storm morphology and evolution only depend on the shape and length of a hodograph, on which the storm-relative winds depend; that is, storm characteristics are independent of the translation and rotation of a hodograph. Therefore, traditional definitions of directional and speed shear are most relevant when applied to the storm-relative wind profile.
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SURESH, R. "An account of low level wind shear over Chennai airport - Part II : Turbulence and eddy dissipation." MAUSAM 60, no. 3 (November 27, 2021): 325–42. http://dx.doi.org/10.54302/mausam.v60i3.1104.

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In-flight reports on Low Level Wind Shear (LLWS) received from aircrafts are used to issue wind shear alerts for all subsequent landing aircrafts as per standing guidelines of International Civil Aviation Organisation (ICAO). In this paper, winds reported by aircrafts at 1000 and 1800 ft. are used to validate the wind estimated from DWR measured radial wind data employing standard algorithms. Turbulence indices and parameters have been computed independently using conventional (RS/RW) upper air data, aircraft measured winds and DWR estimated winds and compared these with wind shear induced turbulence reported by aircrews. Mean power law (wind escalation law) profiles in the boundary layer have been arrived at for unstable and stable atmospheric conditions. Three dimensional shear (3DS) upto 600 m a.g.l. has been worked out from DWR measured radial velocity data and compared with wind shear computed from RS/RW and aircraft measured winds and DWR estimated winds. It is found that 3DS values of more than 16 * 10-3 s-1 predict well the occurrence of moderate turbulence. Contrary to the general belief that wind shear is a short lived phenomenon which may last for a few minutes only, it has been observed that incidences of LLWS and induced moderate turbulence lasting more than 10 hrs are not at all uncommon over Chennai aircraft.
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Madougou, Saïdou, Frederique Saïd, Bernard Campistron, and Fadel Kebe Cheikh. "Low Level Jet Wind Shear in the Sahel." International Journal of Engineering Research in Africa 11 (October 2013): 1–10. http://dx.doi.org/10.4028/www.scientific.net/jera.11.1.

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In the Sahel, a vertical wind shear appears in the dry and in the wet seasons. In Niamey, Niger, during the dry season, the period of strong shears is clearly linked to the Nocturnal Low Level Jet (LLJ) since it occurs in a narrow time period around 06H00 UTC at 60% of the cases reach shears which require an alert to the pilots (higher than 4 ms-1 per 100 m). The majority of cases occur during the night with a wind shear direction between 90 and 150° per 100 m, which is shown that it is dangerous for aircraft. In Bamako, Mali, high wind shears represent (higher than 4 ms-1 per 100 m) only 16-22% of the cases and can occur at any time of the day. There are, however, 8% of the cases, the whole day long, when the wind shear can reach more than 6 ms-1 per 100 m. Most of the wind shear directions are also between 0 and 90° per 100 m during the night. This is why the Agency for the safety of aircraft navigation in Africa and Madagascar (ASECNA) has put in 2004 at Bamako airport an UHF wind profiler radar for monitoring nocturnal strong Low Level Jet wind shear which occur regularly in this airport.
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Velden, Christopher S., and John Sears. "Computing Deep-Tropospheric Vertical Wind Shear Analyses for Tropical Cyclone Applications: Does the Methodology Matter?" Weather and Forecasting 29, no. 5 (October 1, 2014): 1169–80. http://dx.doi.org/10.1175/waf-d-13-00147.1.

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Abstract Vertical wind shear is well known in the tropical cyclone (TC) forecasting community as an important environmental influence on storm structure and intensity change. The traditional way to define deep-tropospheric vertical wind shear in most prior research studies, and in operational forecast applications, is to simply use the vector difference of the 200- and 850-hPa wind fields based on global model analyses. However, is this rather basic approach to approximate vertical wind shear adequate for most TC applications? In this study, the traditional approach is compared to a different methodology for generating fields of vertical wind shear as produced by the University of Wisconsin Cooperative Institute for Meteorological Satellite Studies (CIMSS). The CIMSS fields are derived with heavy analysis weight given to available high-density satellite-derived winds. The resultant isobaric analyses are then used to create two mass-weighted layer-mean wind fields, one upper and one lower tropospheric, which are then differenced to produce the deep-tropospheric vertical wind shear field. The principal novelty of this approach is that it does not rely simply on the analyzed winds at two discrete levels, but instead attempts to account for some of the variable vertical wind structure in the calculation. It will be shown how the resultant vertical wind shear fields derived by the two approaches can diverge significantly in certain situations; the results also suggest that in many cases it is superior in depicting the wind structure's impact on TCs than the simple two-level differential that serves as the common contemporary vertical wind shear approximation.
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Han, Ying, and Boualem Khouider. "Convectively Coupled Waves in a Sheared Environment." Journal of the Atmospheric Sciences 67, no. 9 (September 1, 2010): 2913–42. http://dx.doi.org/10.1175/2010jas3335.1.

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Abstract A linear stability analysis, about a radiative–convective equilibrium in a sheared environment, on an equatorial beta plane, for a simple multicloud model for organized tropical convection is presented here. Both vertical/baroclinic and meridional/barotropic zonal wind shears are considered separately in a parameter regime for which the shear-free multicloud model exhibits synoptic-scale instability of Kelvin and n = 0 eastward inertio-gravity [eastward mixed Rossby–gravity (MRG)] waves only, with moderate growth rates. The maximum growth rates appear to increase significantly with the strength of the background wind shear, and new wave instabilities appear and/or disappear depending on the strength and type of the wind shear. It is found here that both high- and low-level vertical shears have a strong impact on the stability of convectively coupled waves (CCWs), consistent with the fact that the multicloud instability mechanism is controlled by both stratiform heating and low-level moisture and congestus heating. Typically, vertical shears with high-level easterly wind destabilize westward moving waves and stabilize eastward waves, whereas westerly winds aloft and on bottom tend to destabilize eastward moving and stabilize westward moving waves. In the mixed situation of high-level easterlies and low-level westerlies both eastward and westward waves are unstable, while in the case of high-level westerlies and low-level easterlies only eastward waves are unstable. In the presence of a barotropic/meridional shear, synoptic-scale convectively coupled westward MRG and Rossby waves emerge, when the shear strength is large enough, due essentially to pure shear instability of the dry dynamics. The meridional shear has also an important impact on the horizontal structure of the waves. Owing to the meridional shear, the Kelvin wave displays a nonzero meridional velocity that induces a significant contribution toward the horizontal convergence. The two-day waves adopt a crescentlike shape while the westward MRG, and somewhat the Rossby waves, become less trapped in the vicinity of the equator.
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Khalid, Mahmood. "Crosswise Wind Shear Represented as a Ramped Velocity Profile Impacting a Forward-Moving Aircraft." International Journal of Aerospace Engineering 2019 (August 18, 2019): 1–18. http://dx.doi.org/10.1155/2019/7594737.

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Abrupt changes in wind velocities over small distances in a lateral or vertical direction can produce wind shear which is known to have serious effects upon the performance of an aircraft. Brought about by large-scale changes in the atmospheric conditions, it is a three-dimensional flow phenomenon imposing severe velocity gradients on an aircraft from all possible directions. While it would be difficult to model an instantaneous velocity gradient in a lateral plane, a vortical flow impinging from the sides which represents a wind shear in a vertical direction is imposed on a forward-moving aircraft to investigate the effect on the aerodynamic performance. The maximum shear wind speed from the side was fixed at 0.3 times the forward velocity. After due validations under no-wind shear conditions on simpler half-reflection plane models, a BGK airfoil-based full 3D wing and the ONERA M6 3D wing model were selected for preliminary studies. The investigation was concluded using the ARA M100 wing-fuselage model.
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SURESH, R. "On nowcasting wind shear induced turbulence over Chennai air field." MAUSAM 55, no. 1 (January 19, 2022): 103–18. http://dx.doi.org/10.54302/mausam.v55i1.933.

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With the newly installed Doppler Weather Radar at Cyclone Detection Radar station, Chennai during October 2001, it has been made possible to analyse the meteorological conditions conducive for the wind shear induced turbulence experienced by the pilots in the approach runway at the time of landing and take-off. The radar has been put into operation w.e.f. 21 February, 2002. Wind shears reported during February – October 2002, have been critically analysed in this study. The three dimensional shear (3DS), a combination of radial, azimuthal and elevation shears, gives a first hand information atleast half an hour before the occurrence of shear induced moderate turbulence when its value exceeds 16mps/km. The 3DS of more than 20mps/km is normally associated with turbulence experienced by the pilots. With the availability of sophisticated and vast computing power, it is now possible to delineate the layer at which the shear is active within 3-5 minutes from the receipt of the radar measured volume data by quickly computing elevation / vertical / radial / azimuthal shear etc. However, to arrive at a meaningful conclusion on the threshold values of shears that are conducive for wind shear induced turbulence and to make use of this information to alert the pilots, feed back from the pilots to build a detailed data base is absolutely inevitable. Monitoring of passage of sea breeze front may also be useful to issue wind shear warnings. The time tested Richardson number has also been verified for its ‘outlook predictability’ of the shear induced turbulence around the airport, though it can not pinpoint the exact location and the time at which turbulence is active. It is hoped that with precise, accurate and timely in-flight report about the wind shear experienced by the pilots and based on the experience gained in analyzing such information, it will be possible to issue probable ‘wind shear alert / warning’ in the near future.
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Dissertations / Theses on the topic "Wind shear"

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Belderrain, José Luiz Rocha. "Desempenho ótimo de aviões voando em "wind-shear"." Instituto Tecnológico de Aeronáutica, 1991. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=1785.

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Esta dissertação considera a aplicação da teoria de controle ótimo a um avião que está voando através de "wind-shear"; para reduzir o efeito da força desaceleradora aplicada pela massa de ar que pode ser da mesma ordem de magnitude que o arrasto total da aeronave o índice de desempenho escolhido é a minimização dos desvios da trajetória atual em relação a uma trajetória nominal. O cenário do problema e o modelamento matemático são bastante realistas, tendo sido utilizado para a aeronave um modelo de corpo rígido. Foi com sucesso tanto pelo método "exato" (estrutura de contato) como por um método aproximedo uma limitação de ângulo de ataque. Para resolver o problema matemático resultante (sistema de equações diferenciais ordinárias com múltiplas condições de contorno) foram utilizados, conjuntamente, o método dos múltiplos tiros e um método de homotopia modificado. Desta forma, foram obtidas várias trajetórias ótimas, onde se nota que a estratégia básica de controle é a manutenção da velocidade em relação ao solo. Algumas leis de controle simplificadas foram analisadas; as leis de atitude longitudinal constante, de realimentação do ângulo da trajetória e de realimentação da aceleração na direção da trajetória apresentaram um desempenho semelhante, ligeiramente inferior ao ótimo. Possivelmente, uma lei de controle mais elaborada conseguiria reproduzir, com boa aproximação, as trajetórias ótimas.
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Guldsten, Jon Didriksen. "Influence on wind shear and turbulence in flow over obstacles." Thesis, Norwegian University of Science and Technology, Department of Energy and Process Engineering, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-10029.

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A wind tunnel study of speed-up effects above the very crest of a sharp-edged escarpment and a hill peak in a simulated atmospheric boundary layer has been carried out. It was desired to do a part-deep simulation of an atmospheric boundary that could be found above sea or coastal area exposed to the open sea. Because of the limited work section length was it used a modified roughness, barrier and mixing-device developed by Counihan to accelerate the boundary layer growth. The mean velocity, integral length scales, power spectrum and turbulence intensity in the simulated boundary layer were compared with full scale empirical data. It showed good agreement except for the turbulence intensity which was too low. Speed-up effects for the mean horizontal velocity and the longitudinal turbulence intensity above the very crest of an escarpment and a hill peak were investigated in the simulated atmospheric boundary layer. From the results it was observed that the speed-up effect gave a decrease in the turbulence intensity and a more uniform profile with height. A considerably increase of the horizontal mean velocity in the lowest part of the flow was also observed. Scaled-up data from the wind tunnel experiment were compared with estimations from the Norwegian standard and potential flow with varying degree of agreement.

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Zarraonandia, Gaizka. "Influence on wind shear and turbulence in flow over obstacles." Thesis, Norwegian University of Science and Technology, Department of Energy and Process Engineering, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-10165.

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A wind tunnel study of speed-up effects above the very crest of a sharp-edged escarpment and a hill peak in a simulated atmospheric boundary layer has been carried out. It was desired to do a part-depth simulation of an atmospheric boundary that could be found above sea or coastal area exposed to the open sea. Because of the limited work section length it was used a modified roughness, barrier and mixing-device method developed by Counihan to accelerate the boundary layer growth. The mean velocity, integral length scales, power spectrum and turbulence intensity in the simulated boundary layer were compared with full scale empirical data. It showed good agreement except for the turbulence intensity which was too low. Speed-up effects for the mean horizontal velocity and the longitudinal turbulence intensity above the very crest of an escarpment and a hill peak were investigated in the simulated atmospheric boundary layer. From the results it was observed that the speed-up effect gave a decrease in the turbulence intensity and a more uniform profile with height. In addition, it was observed a considerably increase of the horizontal mean velocity in the lowest part of the atmospheric boundary layer. Scaled-up data from the wind tunnel experiment were compared with estimations from the Norwegian standard and potential flow with varying degree of agreement.

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Caeiro, Olaio Valente Maria Antonia. "Effects of directional wind shear on orographic gravity wave drag." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325212.

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Indriyanto, Toto. "Nonlinear flight control system for lateral manoeuvres in wind shear." Thesis, Cranfield University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273525.

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Guarino, Maria Vittoria. "Mountain wave breaking in atmospheric flows with directional wind shear." Thesis, University of Reading, 2017. http://centaur.reading.ac.uk/75850/.

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In this thesis, mountain wave breaking triggered by directional wind shear is investigated using numerical simulations of idealized and semi-idealized orographic flows. Idealized simulations are used to produce a regime diagram to diagnose conditions for wave breaking in Richardson number-dimensionless mountain height parameter space. It is found that, in the presence of directional shear, wave breaking can occur over lower mountains than in a constant-wind case. Furthermore, the extent of regions within the simulation domain where Clear-Air Turbulence (CAT) is expected increases with terrain elevation and background wind shear intensity. Analysis of the model output, supported by theoretical arguments, suggest the existence of a link between wave breaking and the relative orientations of the incoming wind vector and the horizontal velocity perturbation vector. This condition provides a possible diagnostic for CAT forecast in directional shear flows. The stability of the flow to wave breaking in the transition from hydrostatic to nonhydrostatic mountain waves is also investigated. Wave breaking seems to be inhibited by non-hydrostatic effects for weak wind shear, but enhanced for stronger wind shear. In the second part of the thesis, a turbulence encounter observed over the Rocky Mountains (in Colorado, USA) is studied. The role of directional shear in causing wave breaking is isolated from other possible wave breaking mechanisms through various sensitivity tests. The existence of an asymptotic wake, as predicted by Shutts for directional shear flows, is hypothesized to be responsible for a significant downwind transport of unstable air detected in cross-sections of the flow. Finally, critical levels induced by directional shear are studied by spectral analysis of the horizontal velocity wave perturbations. This is done for a fully idealized flow and for the more realistic flow corresponding to the investigated turbulence encounter. In these 2D power spectra, a rotation of the most energetic wave modes with the background wind and their selective absorption can be found. Such behaviour is consistent with the mechanism leading to wave breaking in directional shear flows.
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Baseer, Mohammed Abdul. "Wind resource assessment and GIS-based site selection methodology for efficient wind power deployment." Thesis, University of Pretoria, 2017. http://hdl.handle.net/2263/61314.

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An enormous and urgent energy demand is predicted due to the growing global population, increase in power intensive industries, higher living standards, electrification of remote areas, and globalisation (transportation). Moreover, the global consciousness about the harmful effects of traditional methods of power generation on the environment. That, in turn, has created a need to strategically plan and develop renewable and sustainable energy generation systems. This study presents a wind resource assessment of seven locations proximate to the largest industrial hub in the Middle East, Jubail Industrial City, Kingdom of Saudi Arabia, and a Geographic Information System, GIS based model considering a multi-criteria wind farm site suitability approach for the entire Kingdom of Saudi Arabia and elsewhere. The hourly mean wind speed data at 10, 50 and 90 m above the ground level (AGL) over a period of five years was used for a meteorological station at the Industrial Area (Central) of Jubail. At the remaining six sites, the meteorological data were recorded at 10 m AGL only. Five years of wind data were used for five sites and three years of data were available for the remaining one site. At the Industrial Area (East), the mean wind speeds were found to be 3.34, 4.79 and 5.35 m/s at 10, 50 and 90 m AGL, respectively. At 50 and 90 m AGL, the availability of wind speed above 3.5 m/s was more than 75%. The local wind shear exponent, calculated using measured wind speed values at three heights, was found to be 0.217. The mean wind power density values at measurement heights were 50.92, 116.03 and 168.46 W/m2, respectively. After the assessment and comparison of wind characteristics of all seven sites, the highest annual mean wind speed of 4.52 m/s was observed at Industrial Area (East) and the lowest of 2.52 m/s at the Pearl Beach with standard deviations of 2.52 and 1.1 m/s, respectively. In general, at all sites, the highest monthly mean wind speed was observed in February/June and the lowest in September/October. The period of higher wind availability coincides with a high power demand period in the region attributable to the air conditioning load. The wind rose plots show that the prevailing wind direction for all sites was from the north-west. Weibull parameters for all sites were estimated using maximum likelihood, least-squares regression method (LSRM), and WAsP algorithm. In general, at all sites, the Weibull parameter, c, was the highest in the months of February/June and the lowest in the month of October. The most probable and maximum energy carrying wind speed was determined by all three methods. The highest value of most probable wind speed was found to be in the range of 3.2 m/s to 3.6 m/s at Industrial Area (East) and the highest value of maximum energy carrying wind speed was found to be in the range 8.6 m/s to 9.0 m/s at Industrial Area 2 (South) by three estimation methods. The correlation coefficient (R2), root mean square error (RMSE), mean bias error (MBE), and mean bias absolute error (MAE) showed that all three methods represent wind data at all sites accurately. However, the maximum likelihood method is slightly better than LSRM, followed by WAsP algorithm. The wind power output at all seven sites, from five commercially available wind turbines of rated power ranging from 1.8 to 3.3 MW, showed that Industrial Area (East) is most promising for wind farm development. At all sites, based on percentage plant capacity factor, PCF, the 1.8 MW wind turbine was found to be the most efficient. At Industrial Area (East), this wind turbine was found to have a maximum PCF of 41.8%, producing 6,589 MWh/year energy output. The second best wind turbine was 3 MW at all locations except the Al-Bahar Desalination Plant and Pearl Beach. At both of these locations, 3.3 MW was the next best option. The energy output from the 3 MW wind turbine at Industrial Area (East) was found to be 11,136 MWh/year with a PCF of 41.3%. The maximum duration of rated power output from all selected wind turbines was observed to be between 8 to 16.6% at Industrial Area 2 (South). The minimum duration of rated power output, less than 0.3% for all wind turbines, was observed at Pearl Beach. The maximum duration of zero power output of between 35 to 60% was also observed at Pearl Beach.
Thesis (PhD)--University of Pretoria, 2017.
Mechanical and Aeronautical Engineering
PhD
Unrestricted
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Stival, Leandro Jose Lemes. "A study on wind assessment on the wind power performance : wind shear and turbulence intensity effects besides the wake modeling for a single wind turbine." reponame:Repositório Institucional da UFPR, 2017. http://hdl.handle.net/1884/49088.

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Orientador : Prof. Dr. Alexandre Kolodynskie Guetter
Coorientador : Prof. Dr. Fernando Oliveira Andrade
Dissertação (mestrado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Engenharia de Recursos Hídricos e Ambiental. Defesa: Curitiba, 04/04/2017
Inclui referências : f.91-97
Resumo: A energia eólica cresceu significativamente, porém a eficiência de geração da fonte eólica gira em torno de 30% da energia cinética disponível no vento. Por este motivo é de extrema importância que estudos sejam elaborados afim de aumentar a eficiência na geração de energia. Este estudo visa investigar odesempenho da geração de energia eólica em dois parques eólicos situadosna América do Norte, através da investigação dos dados de vento e modelagem da esteira turbulenta. Os dados analisados são provenientes da turbina, SCADA, e dados coletados pelo LiDAR. A partir das análises dos dados de vento foram estimados parâmetros como tensão de cisalhamento do vento, rosa dos ventos, perfil de velocidade do vento e intensidade de turbulência. Portanto, aumentando a intensidade de turbulência, a energia gerada é superestimada em moderadas velocidades do vento e subestimada em altas velocidades do vento. Enquanto isso, os coeficientes de cisalhamento do vento variaram entre 0 e 0.2 para altas velocidades. Além disso, coeficientes de cisalhamento com valores elevados, perto de 0.4, foram encontrados em baixas velocidades do vento. Este trabalho visou também comparar modelos de esteira turbulenta de PARK (Jensen), Frandsen, Larsen and Eddy Viscosity (Ainslie) com resultados obtidos pelo LiDAR, além disso foi realizado uma simulação numérica da esteira turbulenta utilizando Fluent CFD com as equações médias de Reynolds (RANS) que resolvem o modelos de duas equações diferenciais para obter a viscosidade turbulenta. A turbulência foi fechada pelo modelo ?????, sendo o modelo de esteira turbulenta desenvolvido para uma única turbina num terreno plano. O modelo de PARK obteve os melhores resultados para linha de centro longitudinal em relação as velocidades de 6 a 8 ms-1. Entretanto, para velocidade de 9 a 12 ms-1 , o modelo de EDDY VISCOSITY apresentou o melhor desempenho. As análises de seção transversal apresentaram o modelo de PARK como melhor resultado para 500 m. Enquanto isso, para 700 m de seção transversal, o melhor desempenho foi obtido pelo modelo de LARSEN. Palavras-chave: Energia Eólica, Modelo de Esteira Turbulenta, LiDAR, Análises do Vento.
Abstract: Wind power has gained significant share in the global power production. However, the wind power output efficiency is only about 30% of the wind kinetic energy. Because of that, it is essential to study the efficiency of these power generation systems by assessing the effects that wind parameters and wakes will have on the whole system. Hence, a complete assessment of wind resources is crucial to retain full advantage of wind power. This study aims to investigate the efficiency of wind energy generation in two North American Wind Farms, through wind data investigation and wake modeling. The data analyzed are the SCADA data and the data collected by LiDAR measurements. The wind data analysis has estimated parameters as wind shear, wind rose, wind speed profile and turbulence intensity. Therefore increasing turbulence intensity the power output is overestimated at moderate wind speeds and underestimated at higher wind speeds. Meanwhile, the wind shear coefficients were found to vary between 0 and 0.2 at higher inflow velocities. High wind shear values, close to 0.4, were recorded for lower inflow velocities. The goal of the wake models is to simulate the turbine induced wind speed deficits and the ratio of restoration to the free stream velocity. This work has compared the PARK (Jensen), Frandsen, Larsen and Eddy Viscosity (Ainslie) models with LiDAR wake measurements, besides that it has performed a numerical simulation of the wind turbine wake using the Fluent CFD with the Reynolds Averaged Navier Stokes (RANS) equations that solves two differential equation model to obtain turbulent viscosity. The turbulence was closed by the ????? model, where the wake modeling has been developed for a single turbine on a flat terrain. In terms of centerline wake analysis, the PARK wake model yielded the best velocity simulations for inflow winds from 6 to 8 ms-1. However, the EDDY VISCOSITY wake model yielded the best performance for wind speed bins from 9 to 12 ms-1. The cross section wake analysis presented for the 500 m cross section, the domination by the PARK model. Meanwhile, along the 700 m cross section, the LARSEN wake model produced the best simulations. Key-words: Wind Power, Wake Modeling, LiDAR, Wind Analysis.
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Sycuro, Stephen J. "Radar turbulence estimates : effects of wind shear and reflectivity factor gradients." Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/58128.

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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, 1985.
Microfiche copy available in Archives and Science.
Bibliography: leaf 43.
by Stephen J. Sycuro.
M.S.
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Mu, K. L. "Investigation of tropospheric turbulence using the Adelaide VHF radar /." Title page, abstract and contents only, 1991. http://web4.library.adelaide.edu.au/theses/09SM/09smm941.pdf.

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Books on the topic "Wind shear"

1

Trevino, G. Structure of wind-shear turbulence. Hampton, Va: Langley Research Center, 1989.

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R, Laituri Tony, and United States. National Aeronautics and Space Administration., eds. Structure of wind-shear turbulence. [Washington, DC]: [National Aeronautics and Space Administration, 1988.

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R, Laituri Tony, and United States. National Aeronautics and Space Administration. Scientific and Technical Information Division., eds. Structure of wind-shear turbulence. [Washington, DC]: National Aeronautics and Space Administration, Scientific and Technical Information Division, 1989.

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R, Laituri Tony, and United States. National Aeronautics and Space Administration. Scientific and Technical Information Division., eds. Structure of wind-shear turbulence. [Washington, DC]: National Aeronautics and Space Administration, Scientific and Technical Information Division, 1989.

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R, Laituri Tony, and United States. National Aeronautics and Space Administration., eds. Structure of wind-shear turbulence. [Washington, DC]: [National Aeronautics and Space Administration, 1988.

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Etkin, Bernard. Comment on "Wind shear terms in the equations of aircraft motion". [S.l.]: [s.n.], 1987.

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Hinton, David A. Relative merits of reactive and forward-look detection for wind-shear encounters during landing approach for various microburst escape strategies. [Washington, DC]: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Division, 1990.

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Hinton, David A. A candidate concept for display of forward-looking wind shear information. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1989.

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E, Delnore Victor, and United States. National Aeronautics and Space Administration, eds. Wind shear detection: Forward-looking sensor technology. [Washington, DC]: U.S. Dept. of Transportation, 1987.

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Hinton, David A. Flight-management strategies for escape from microburst encounters. [Washington, D.C.]: National Aeronautics and Space Administration, Scientific and Technical Information Division, 1988.

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Book chapters on the topic "Wind shear"

1

Lundquist, Julie K. "Wind Shear and Wind Veer Effects on Wind Turbines." In Handbook of Wind Energy Aerodynamics, 859–80. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-31307-4_44.

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Lundquist, Julie K. "Wind Shear and Wind Veer Effects on Wind Turbines." In Handbook of Wind Energy Aerodynamics, 1–22. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-05455-7_44-1.

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Li, Xiaofan, and Shouting Gao. "Effects of Vertical Wind Shear." In Precipitation Modeling and Quantitative Analysis, 125–36. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-2381-8_5.

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Miele, A., T. Wang, and G. D. Wu. "Perspectives on Wind Shear Flight." In Modern Research Topics in Aerospace Propulsion, 355–75. New York, NY: Springer New York, 1991. http://dx.doi.org/10.1007/978-1-4612-0945-4_18.

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Kumbhare, Rohit, Suraj Sawant, Sanand Sule, and Amit Joshi. "Wind Speed at Hub Height (Using Dynamic Wind Shear) and Wind Power Prediction." In Advances in Intelligent Systems and Computing, 519–27. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-2008-9_49.

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Poedts, S., A. D. Rogava, and S. M. Mahajan. "Velocity Shear Induced Phenomena in Solar Atmosphere." In Coronal Holes and Solar Wind Acceleration, 295–98. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-015-9167-6_48.

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Atlas, David. "Radar Detection of Low-Level Wind Shear." In Reflections: A Memoir, 113–15. Boston, MA: American Meteorological Society, 2001. http://dx.doi.org/10.1007/978-1-935704-07-2_11.

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Wang, Rui, Dongliang Zhang, Xiangguo Wu, Fei Wang, Tianhao Li, Kun Fu, Wantong Liu, et al. "Shear Behavior Solution of the Shear Keyed Joints for Onshore Wind Foundation." In Lecture Notes in Civil Engineering, 93–103. Singapore: Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-5315-4_10.

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Migliuolo, Stefano. "Velocity Shear Instabilities in the Anisotropic Solar Wind." In Unstable Current Systems and Plasma Instabilities in Astrophysics, 371–74. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-6520-1_39.

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Suárez-Molina, David, and Juan Carlos Suárez González. "Wind Shear Forecast in GCLP and GCTS Airports." In SEMA SIMAI Springer Series, 39–52. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-61795-0_3.

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Conference papers on the topic "Wind shear"

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Bencatel, Ricardo, Anouck Girard, Mariam Abdelhafiz, and João Sousa. "Shear Wind Estimation." In AIAA Guidance, Navigation, and Control Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2011. http://dx.doi.org/10.2514/6.2011-6224.

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CHANG, H. P., D. CAMP, W. FROST, and J. MCCARTHY. "Wind shear characterization." In 24th Aerospace Sciences Meeting. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1986. http://dx.doi.org/10.2514/6.1986-180.

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Galtier, S. "Weak turbulence of anisotropic shear-Alfvén waves." In SOLAR WIND TEN: Proceedings of the Tenth International Solar Wind Conference. AIP, 2003. http://dx.doi.org/10.1063/1.1618648.

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Turner, Trevor B., Ryan F. Schkoda, John R. Wagner, and Robert T. Leitner. "Wind Shear Modeling for Wind Turbine Siting Studies." In ASME 2009 Dynamic Systems and Control Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/dscc2009-2696.

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A wind turbine generator offers a green renewable alternative to the traditional fossil and nuclear fuel processes to generate electrical power. Both wind energy technology and wind turbine farm designs remain in demand given the current growth in energy requirements and the public’s preference for clean sources. Simply put, wind energy offers a safe, relatively cost effective solution for global energy production. For example, the energy demand for populated coastal cities encourages offshore farms to fulfill future electrical needs. Similarly, wind turbines may be placed in land-locked regions and power transmitted through electric grids to population centers. Most wind models available to engineers offer superb capabilities for predicting wind velocities on land and far offshore (5 km and greater). However, near shore winds have proven difficult to determine due to surface roughness, thermal stratification, and abrupt displacement height variances. This paper discusses the model comparison of two foremost wind speed prediction tools, AWS Truewinds’ MASS and WindPro’s WAsP. The model comparison is related to measured South Carolina coastal data and suggests AWS Truewind’s MASS wind shear model is the more effective near-shore wind speed prediction tool. In arriving at these results, several areas of future work are discussed.
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McCullogh, Carl P. "Wind shear detection systems." In Aerospace/Defense Sensing and Controls, edited by Robert G. Otto, James Lenz, and Russell Targ. SPIE, 1996. http://dx.doi.org/10.1117/12.241054.

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ADELFANG, STANLEY, and ORVEL SMITH. "Analysis of extreme wind shear." In 27th Aerospace Sciences Meeting. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1989. http://dx.doi.org/10.2514/6.1989-710.

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Rogers, Anthony, James Manwell, and Anthony Ellis. "Wind Shear over Forested Areas." In 43rd AIAA Aerospace Sciences Meeting and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2005. http://dx.doi.org/10.2514/6.2005-1327.

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Stewart, Susan W. "Offshore Wind Shear Estimations for Wind Power Assessment." In ASME 2008 2nd International Conference on Energy Sustainability collocated with the Heat Transfer, Fluids Engineering, and 3rd Energy Nanotechnology Conferences. ASMEDC, 2008. http://dx.doi.org/10.1115/es2008-54301.

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Appropriate wind shear estimates are extremely important when assessing any regions’ wind power resource. Wind shear is used not only to estimate wind velocity at wind turbine hub heights other than the data collection height, but also as a siting tool to compare the wind resources in different locations when wind data are not available at a consistent height. Models for wind shear over land, as well as simple models for wind shear over open water have been found to correlate poorly with offshore wind data. This is thought to be partially due to the effect of changing wave conditions on wind shear as well as differences in thermal effects over bodies of water. In this study, offshore wind data from the South Atlantic Bight region is used to estimate the offshore wind shear conditions in this area. Data sets include collocated 10 m and 50 m meteorological data as well as wave data, all taken over a three and a half year time period. Offshore wind shear assessments from other studies are analyzed and compared to the current study as well.
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Kim, Eun-jin, Han-Li Liu, Johan Anderson, M. Maksimovic, K. Issautier, N. Meyer-Vernet, M. Moncuquet, and F. Pantellini. "Probability distribution function of self-organization of shear flows." In TWELFTH INTERNATIONAL SOLAR WIND CONFERENCE. AIP, 2010. http://dx.doi.org/10.1063/1.3395862.

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Wan, M., S. Oughton, S. Servidio, W. H. Matthaeus, M. Maksimovic, K. Issautier, N. Meyer-Vernet, M. Moncuquet, and F. Pantellini. "The third-order law for magnetohydrodynamic turbulence with constant shear." In TWELFTH INTERNATIONAL SOLAR WIND CONFERENCE. AIP, 2010. http://dx.doi.org/10.1063/1.3395829.

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Reports on the topic "Wind shear"

1

Poedts, S., A. D. Rogava, and S. M. Mahajan. Shear flow induced wave couplings in the solar wind. Office of Scientific and Technical Information (OSTI), January 1998. http://dx.doi.org/10.2172/582279.

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Rahai, Hamid, and Assma Begum. Numerical Investigations of Transient Wind Shear from Passing Vehicles Near a Road Structure (Part I: Unsteady Reynolds-Averaged Navier-Stokes Simulations). Mineta Transportation Institute, January 2021. http://dx.doi.org/10.31979/mti.2020.1933.

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In this research, the authors performed unsteady numerical simulations of a moving Ahmed body under a freeway overpass at different distances from the bridge columns in order to evaluate transient wind shear and the wind load on these columns. Results have shown that when the vehicle is at 0.75W distance from the bridge columns, an unsteady wind speed of up to 24 m/s is observed at the columns with a pressure coefficient difference of 0.9. Here W is the width of the vehicle. These results indicate with an appropriate system for harnessing these wind energy potentials, significant renewable electric power could be generated with zero carbon footprint.
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Gordon, Randy, Robert Fails, Solomon Baase, Jason Eckberg, Charles Ryan, and Chris Smith. USAF TPS L-23 Shear Wind Observed Optimized Path Investigation for NASA (SENIOR ShWOOPIN). Fort Belvoir, VA: Defense Technical Information Center, June 2006. http://dx.doi.org/10.21236/ada470169.

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Hart, Carl, and Gregory Lyons. A tutorial on the rapid distortion theory model for unidirectional, plane shearing of homogeneous turbulence. Engineer Research and Development Center (U.S.), July 2022. http://dx.doi.org/10.21079/11681/44766.

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The theory of near-surface atmospheric wind noise is largely predicated on assuming turbulence is homogeneous and isotropic. For high turbulent wavenumbers, this is a fairly reasonable approximation, though it can introduce non-negligible errors in shear flows. Recent near-surface measurements of atmospheric turbulence suggest that anisotropic turbulence can be adequately modeled by rapid-distortion theory (RDT), which can serve as a natural extension of wind noise theory. Here, a solution for the RDT equations of unidirectional plane shearing of homogeneous turbulence is reproduced. It is assumed that the time-varying velocity spectral tensor can be made stationary by substituting an eddy-lifetime parameter in place of time. General and particular RDT evolution equations for stochastic increments are derived in detail. Analytical solutions for the RDT evolution equation, with and without an effective eddy viscosity, are given. An alternative expression for the eddy-lifetime parameter is shown. The turbulence kinetic energy budget is examined for RDT. Predictions by RDT are shown for velocity (co)variances, one-dimensional streamwise spectra, length scales, and the second invariant of the anisotropy tensor of the moments of velocity. The RDT prediction of the second invariant for the velocity anisotropy tensor is shown to agree better with direct numerical simulations than previously reported.
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Kamrath, Matthew, Vladimir Ostashev, D. Wilson, Michael White, Carl Hart, and Anthony Finn. Vertical and slanted sound propagation in the near-ground atmosphere : amplitude and phase fluctuations. Engineer Research and Development Center (U.S.), May 2021. http://dx.doi.org/10.21079/11681/40680.

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Sound propagation along vertical and slanted paths through the near-ground atmosphere impacts detection and localization of low-altitude sound sources, such as small unmanned aerial vehicles, from ground-based microphone arrays. This article experimentally investigates the amplitude and phase fluctuations of acoustic signals propagating along such paths. The experiment involved nine microphones on three horizontal booms mounted at different heights to a 135-m meteorological tower at the National Wind Technology Center (Boulder, CO). A ground-based loudspeaker was placed at the base of the tower for vertical propagation or 56m from the base of the tower for slanted propagation. Phasor scatterplots qualitatively characterize the amplitude and phase fluctuations of the received signals during different meteorological regimes. The measurements are also compared to a theory describing the log-amplitude and phase variances based on the spectrum of shear and buoyancy driven turbulence near the ground. Generally, the theory correctly predicts the measured log-amplitude variances, which are affected primarily by small-scale, isotropic turbulent eddies. However, the theory overpredicts the measured phase variances, which are affected primarily by large-scale, anisotropic, buoyantly driven eddies. Ground blocking of these large eddies likely explains the overprediction.
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Borden, Lance. B-1B Wing Shear Bearing Maintenance Repair (SD11). Fort Belvoir, VA: Defense Technical Information Center, August 2004. http://dx.doi.org/10.21236/ada426342.

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Borden, Lance. B-1B Wing Shear Bearing Maintenance Repair (SD11). Fort Belvoir, VA: Defense Technical Information Center, November 2004. http://dx.doi.org/10.21236/ada427948.

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Borden, Lance. B-1B Wing Shear Bearing Maintenance Repair (SD11). Fort Belvoir, VA: Defense Technical Information Center, April 2004. http://dx.doi.org/10.21236/ada421857.

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Grant, Charles. Diaphragm Walls as Permanent Basement Walls in Regions of High Seismicity. Deep Foundations Institute, June 2018. http://dx.doi.org/10.37308/cpf-2012-slwl-1.

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Reinforced concrete structural slurry walls have been used in the United States since the early 1960s. The typical practice, and one that makes the economics of slurry walls particularly attractive, is to design the walls to act as both temporary excavation support and permanent basement walls. They often serve as multi-story basements and below grade parking for buildings, for tunnels, subway stations, and other buried structures. One of the early applications was for a foundation for a subway station in San Francisco, but for the most part they have been used more extensively in regions of low seismicity. The purpose of this report is to investigate the requirements for extension of this practice to more common use in regions of high seismicity. Structural slurry walls are concrete walls constructed below the ground surface. In slurry wall construction, a trench is excavated using a rectangular clamshell bucket or other specialized equipment. During excavation, the trench is held open by introduction of a bentonite or polymer slurry. Steel reinforcement, if required, is lowered into the slurry-filled trench, and concrete is subsequently deposited by tremie, displacing the slurry. The length of trench open at any one time is limited to a typical maximum of about 20 to 24 feet by excavation stability and concrete placement volume considerations. Each individual concrete placement is referred to as a “panel,” and vertical construction joints separate the panels. Temporary “end-stops” are used as formwork to control the geometry of the panel joints, and horizontal reinforcement is discontinuous at the joints. Structural slurry panels range from 1.5 to 5.0 feet thick, 7 to 24 feet long, and up to 300 feet deep. In the United States, panels that are 2.0 to 3.5 feet thick and depths of 40 to 150 feet are commonplace. Structural basement walls support earth pressures acting laterally against the wall, dead and live loads acting vertically, and in-plane shear and flexure from wind and earthquake loads. The design of permanent slurry walls in regions of low or moderate seismicity is often limited to providing the strength necessary to resist out-of-plane soil pressures and vertical dead and live loads from the superstructure and basement framing. Although these walls also transfer in-plane lateral forces from the superstructure into the soils, the walls are often not specifically designed for these in-plane forces because their inherent strength is usually much greater than the forces being transferred. If resistance to in-plane forces acting on a wall required an increase in vertical reinforcement at the ends of a wall segment, an increase in the cap beam strength, or an increase in the horizontal reinforcement for shear strength, the overall design and construction approach would not vary significantly from current practice. Structural slurry walls have been used to a limited extent for buildings designed for high seismic risk, but there is reluctance on the part of design engineers to use them more often because of concern for how to design these walls to resist in-plane lateral forces, lack of code provisions for reinforcement detailing, and damage that may occur at panel joints. For buildings designed for high seismic risk, such as those assigned to Seismic Design Categories (SDC) D, E, and F as defined in Minimum Design Loads for Buildings and Other Structures (ASCE/SEI 7-10), in-plane shear and flexural actions may likely require modifications of a structural slurry wall only designed for out-of-plane soil pressures and vertical live and dead loads. Design would need to address in-plane lateral forces acting on structural slurry walls and the interaction of the in-plane actions with the out-of-plane and vertical actions. These issues are discussed in this report, and approaches to design for high seismic risk are presented.
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STABILITY PERFORMANCE AND WIND TUNNEL TEST OF STEEL HYPERBOLIC COOLING TOWER CONSIDERING SKINNED EFFECT. The Hong Kong Institute of Steel Construction, September 2023. http://dx.doi.org/10.18057/ijasc.2023.19.3.10.

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With the development of industry, cooling towers play a very important role in thermal power generation, and steel cooling towers are being used more widely. The surface of cooling towers is covered with profiled panels, and the skinned effect on the mechanical performance and stability of the structure should be considered. At present, most studies on steel cooling towers have not considered the skinned effect. In steel cooling towers, the skin panels are usually connected to members by self-tapping screws., the shearing test of self-tapping screw connection is carried out considering different screw diameters and plate thicknesses to obtain the shear stiffness of the screws. Then, three FE models of steel hyperbolic cooling towers are established and compared: in Mode–1, the skin panel is not considered; in Model–2, the panel and the member node are rigidly connected; in Model–3, the spring elements are established to simulate the shearing and tension stiffness of self-tapping screws connecting skin panel and members. Based on the finest Model–3, a parametric analysis is done to investigate the effect of the skinned effect on the overall structural stability. Considering different landform types and the roughness of the inner and outer surfaces, a total of 18 measurement conditions are tested in the wind tunnel to study the outer and internal wind pressure coefficients. Furthermore, based on the wind tunnel test, the wind-induced response analysis of steel hyperbolic cooling towers is performed.
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