Journal articles on the topic 'Wind speed'
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Ni, Weicheng, Ad Stoffelen, Kaijun Ren, Xiaofeng Yang, and Jur Vogelzang. "SAR and ASCAT Tropical Cyclone Wind Speed Reconciliation." Remote Sensing 14, no. 21 (November 2, 2022): 5535. http://dx.doi.org/10.3390/rs14215535.
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Wind speed reconciliation across different wind sources is critically needed for extending available satellite wind records in Tropical Cyclones. The deviations between wind references of extremes, such as the moored buoy data and dropsonde wind estimates for guidance on geophysical model function development, are one of the main causes of wind speed differences for wind products, for instance, the overestimation of Synthetic Aperture Radars (SARs) relative to ASCAT winds. The study proposes a new wind speed adjustment to achieve mutual adjustment between ASCAT CMOD7 winds and simultaneous SAR wind speeds. The so-called CMOD7D-v2 adjustment is constructed based on the statistical analysis of SAR and ASCAT Tropical Cyclone acquisitions between 2016 and 2021, showing a satisfactory performance in wind speed reconciliation for winds with speeds higher than 14 m/s. Furthermore, the error characteristics of the CMOD7D-v2 adjustment for Tropical Cyclone winds are analyzed using the Triple Collocation analysis technique. The analysis results show that the proposed wind adjustment can reduce ASCAT wind errors by around 16.0% when adjusting ASCAT winds to SAR wind speeds. In particular, when downscaling SAR winds, the improvement in ASCAT wind errors can be up to 42.3%, effectively alleviating wind speed differences across wind sources. Furthermore, to avoid the impacts of large footprints by ASCAT sensors, wind speeds retrieved from SAR VV signals (acting as a substitute for ASCAT winds) are adjusted accordingly and compared against SAR dual-polarized winds and collocated Stepped Frequency Microwave Radiometer (SFMR) observations. We find that the bias values of adjusted winds are lower than products from other adjustment schemes by around 5 m/s at the most extreme values. These promising results verify the plausibility of the CMOD7D-v2 adjustment, which is conducive to SAR and ASCAT wind speed comparisons and extreme wind analysis in Tropical Cyclone cases.
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Li, Gang, Juan Cui, Tingshan Liu, Yongqiu Zheng, Congcong Hao, Xiaojian Hao, and Chenyang Xue. "Triboelectric-Electromagnetic Hybrid Wind-Energy Harvester with a Low Startup Wind Speed in Urban Self-Powered Sensing." Micromachines 14, no. 2 (January 23, 2023): 298. http://dx.doi.org/10.3390/mi14020298.
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Wind energy as a renewable energy source is easily available and widely distributed in cities. However, current wind-energy harvesters are inadequate at capturing energy from low-speed winds in urban areas, thereby limiting their application in distributed self-powered sensor networks. A triboelectric–electromagnetic hybrid harvester with a low startup wind speed (LSWS-TEH) is proposed that also provides output power within a wide range of wind speeds. An engineering-implementable propeller design method is developed to reduce the startup wind speed of the harvester. A mechanical analysis of the aerodynamics of the rotating propeller is performed, and optimal propeller parameter settings are found that greatly improved its aerodynamic torque. By combining the high-voltage output of the triboelectric nanogenerator under low-speed winds with the high-power output of the electromagnetic generator under high-speed winds, the harvester can maintain direct current output over a wide wind-speed range after rectification. Experiments show that the harvester activates at wind speeds as low as 1.2 m/s, powers a sensor with multiple integrated components in 1.7 m/s wind speeds, and drives a Bluetooth temperature and humidity sensor in 2.7 m/s wind speeds. The proposed small, effective, inexpensive hybrid energy harvester provides a promising way for self-powered requirements in smart city settings.
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Obukhov, S. G. "DYNAMIC WIND SPEED MODEL FOR SOLVING WIND POWER PROBLEMS." Eurasian Physical Technical Journal 17, no. 1 (June 2020): 77–84. http://dx.doi.org/10.31489/2020no1/77-84.
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Clarizia, Maria Paola, and Christopher S. Ruf. "Bayesian Wind Speed Estimation Conditioned on Significant Wave Height for GNSS-R Ocean Observations." Journal of Atmospheric and Oceanic Technology 34, no. 6 (June 2017): 1193–202. http://dx.doi.org/10.1175/jtech-d-16-0196.1.
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AbstractSpaceborne Global Navigation Satellite System reflectometry observations of the ocean surface are found to respond to components of roughness forced by local winds and to a longer wave swell that is only partially correlated with the local wind. This dual sensitivity is largest at low wind speeds. If left uncorrected, the error in wind speeds retrieved from the observations is strongly correlated with the significant wave height (SWH) of the ocean. A Bayesian wind speed estimator is developed to correct for the long-wave sensitivity at low wind speeds. The approach requires a characterization of the joint probability of occurrence of wind speed and SWH, which is derived from archival reanalysis sea-state records. The Bayesian estimator is applied to spaceborne data collected by the Technology Demonstration Satellite-1 (TechDemoSat-1) and is found to provide significant improvement in wind speed retrieval at low winds, relative to a conventional retrieval that does not account for SWH. At higher wind speeds, the wind speed and SWH are more highly correlated and there is much less need for the correction.
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Tang, Brian H., and Nick P. Bassill. "Point Downscaling of Surface Wind Speed for Forecast Applications." Journal of Applied Meteorology and Climatology 57, no. 3 (March 2018): 659–74. http://dx.doi.org/10.1175/jamc-d-17-0144.1.
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AbstractA statistical downscaling algorithm is introduced to forecast surface wind speed at a location. The downscaling algorithm consists of resolved and unresolved components to yield a time series of synthetic wind speeds at high time resolution. The resolved component is a bias-corrected numerical weather prediction model forecast of the 10-m wind speed at the location. The unresolved component is a simulated time series of the high-frequency component of the wind speed that is trained to match the variance and power spectral density of wind observations at the location. Because of the stochastic nature of the unresolved wind speed, the downscaling algorithm may be repeated to yield an ensemble of synthetic wind speeds. The ensemble may be used to generate probabilistic predictions of the sustained wind speed or wind gusts. Verification of the synthetic winds produced by the downscaling algorithm indicates that it can accurately predict various features of the observed wind, such as the probability distribution function of wind speeds, the power spectral density, daily maximum wind gust, and daily maximum sustained wind speed. Thus, the downscaling algorithm may be broadly applicable to any application that requires a computationally efficient, accurate way of generating probabilistic forecasts of wind speed at various time averages or forecast horizons.
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Matsyura, Alex, Kazimierz Jankowski, and Marina Matsyura. "BIRDS’ FLIGHT ENERGY PREDICTIONS AND APPLICATION TO RADAR-TRACKING STUDY." Biological Bulletin of Bogdan Chmelnitskiy Melitopol State Pedagogical University 3, no. 03 (October 28, 2013): 135. http://dx.doi.org/10.15421/20133_45.
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<p>In offered research, we propose to observe diurnal soaring birds to check, whether there the positions of birds in formations are such, that the wing tip interval and depth meet the predictions of aerodynamic theory for achievement of maximal conservation of energy or predictions of the hypothesis of communication. We also can estimate, whether adverse conditions of a wind influence the ability of birds to support formation. We can assume that windy conditions during flight might make precision flight more difficult by inducing both unpredictable bird and vortex positions. To this, we need to found change in wing-tip spacing variation with increasing wind speed, suggesting or rejecting that in high winds bird skeins maintained similar variation to that on calm days. The interrelation between variation of mean depth and wind speed should prove this hypothesis. Little is known about the importance of depth, but in high winds the vortex is likely to break up more rapidly and its location become unpredictable the further back a bird flies; therefore, a shift towards skeins with more regular depths at high wind speeds may compensate for the unpredictability of the vortex locations. Any significant relationship between the standard deviation of wing-tip spacing and wind speed suggests that wind has a major effect on optimal positioning.</p> <p>Results of proposed study will be used also as the auxiliary tool in radar research of bird migration, namely in research of flight features of soaring birds. It is extremely important to determine all pertinent characteristics of flock for model species, namely flocking birds.</p> <p><em>Kew words: birds, flock, radar, flight</em></p><p> </p>
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Manaster, Andrew, Lucrezia Ricciardulli, and Thomas Meissner. "Validation of High Ocean Surface Winds from Satellites Using Oil Platform Anemometers." Journal of Atmospheric and Oceanic Technology 36, no. 5 (May 2019): 803–18. http://dx.doi.org/10.1175/jtech-d-18-0116.1.
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AbstractReliable sources for validating wind observations made by spaceborne microwave radiometer and scatterometer sensors above 15 m s−1 are scarce. Anemometers mounted on oil platforms provide usable wind speed measurements that can help fill this gap. In our study we compare wind speed observations from six microwave satellites (WindSat, AMSR-E, AMSR2, SMAP, QuikSCAT, and ASCAT) with wind speed records from 10 oil platform anemometers in the North and Norwegian Seas that were provided by the Norwegian Meteorological Institute. We study various forms of the vertical wind profile, which is required to convert anemometer winds to a reference height of 10 m above sea level. We create and analyze matchups between satellite and anemometer winds and find good agreement up to wind speeds of 30 m s−1 within the margin of errors. We also evaluate wind speeds from several analyses [ECMWF, NCEP, and Cross-Calibrated Multi-Platform (CCMP)]. We find them to be significantly lower than the anemometer winds with their biases increasing systematically with increasing wind speed. Important components of our analysis include a detailed discussion on the quality control of the anemometer winds and a quantitative analysis of the uncertainties in creating the matchups.
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Epstein, Lewis. "Wind force and wind speed." Physics Teacher 29, no. 4 (April 1991): 196–97. http://dx.doi.org/10.1119/1.2343275.
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González-González, Asier, and Jose Manuel Lopez-Guede. "Longitudinal wind speed time series generation to wind turbine controllers tuning." International Journal of Renewable Energy Development 7, no. 3 (December 15, 2018): 199–204. http://dx.doi.org/10.14710/ijred.7.3.199-204.
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Although there are a wide variety of applications that require wind speed time series (WSTS), this paper emphases on WSTS to be used into wind turbine controllers tuning. These simulations involve several WSTS to perform a proper assessment. These WSTS must assure realistic wind speed variations such as wind gusts and include some rare events such as extreme wind situations. The architecture proposed to generate this WSTS is based on autoregressive models with certain post-processing. The methodology used is entirely described by precise notation as well as it is parametrized by means of data gathered from a weather station. Two main different simulations are performed and assessment; the first simulation is fed by weather data with high wind speed and great variability. The second simulation, on the opposite, use calm wind speed as a data source.Article History: Received 1st June 2018; Received in revised form Sept 6th 2018; Accepted October 10th 2018; Available onlineHow to Cite This Article: González, A.G. and Guede, J.M.L. (2018) Longitudinal Wind Speed Time Series Generated With Autoregressive Methods For Wind Turbine Control. International Journal of Renewable Energy Development, 7(3), 199-204.https://doi.org/10.14710/ijred.7.3.199-204
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van Zadelhoff, G. J., A. Stoffelen, P. W. Vachon, J. Wolfe, J. Horstmann, and M. Belmonte Rivas. "Scatterometer hurricane wind speed retrievals using cross polarization." Atmospheric Measurement Techniques Discussions 6, no. 4 (August 28, 2013): 7945–84. http://dx.doi.org/10.5194/amtd-6-7945-2013.
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Abstract. Hurricane-force wind speeds can have a large societal impact and in this paper microwave C-band cross-polarized (VH) signals are investigated to assess if they can be used to derive extreme wind speed conditions. European satellite scatterometers have excellent hurricane penetration capability at C-band, but the vertically (VV) polarized signals become insensitive above 25 m s−1. VV and VH polarized backscatter signals from RADARSAT-2 SAR imagery acquired during severe hurricane events were compared to collocated SFMR wind measurements acquired by NOAA's hurricane-hunter aircraft. From this data set a Geophysical Model Function (GMF) at strong-to-extreme/severe wind speeds (i.e. 20 m s−1 < U10 < 45 m s−1) is derived. Within this wind speed regime, cross-polarized data showed no distinguishable loss of sensitivity and as such, cross-polarized data can be considered a good candidate for the retrieval of strong-to-severe wind speeds from satellite instruments. The upper limit of 45 m s−1 is defined by the currently available collocated data. The validity of the derived relationship between wind speed and VH has been evaluated by comparing the cross polarized signals to two independent wind speed datasets, i.e. short-range ECMWF Numerical Weather Prediction (NWP) model forecast winds and the NOAA best estimate one-minute maximum sustained winds. Analysis of the three comparison data sets confirm that cross-polarized signals from satellites will enable the retrieval of strong-to-severe wind speeds where VV or horizontal (HH) polarization data has saturated. The VH backscatter increases exponentially with respect to wind speed (linear against VH [dB]) and a near real time assessment of maximum sustained wind speed is possible using VH measurements. VH measurements thus would be an extremely valuable complement on next-generation scatterometers for Hurricane forecast warnings and hurricane model initialization.
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Gills, Paul A. "WIND AND MAXIMUM WAVE HEIGHT." Coastal Engineering Proceedings 1, no. 5 (January 29, 2011): 30. http://dx.doi.org/10.9753/icce.v5.30.
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The height of waves depends on the strength of the wind it is necessary to know the maximum wind speed in order to know the wave pattern. The data on winds are given by scale (Beaufort's scale), by speed (in nautical miles, or kilometers per hour and meters per second, and the maximum wind speed, typhoons excluded, seems to be 110 miles (nautical). In typhoons the wind speed exceeds these values very much; on the other hand, in the mid-Atlantic zone between the United States and Europe, there are often speeds of 55 miles per hour but greater speeds are exceptional. The experiments on the pressure due to the wind against a body give results which confirm the usual rules of calculations as used in public works, bridges, etc.
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Monahan, Adam H. "The Temporal Autocorrelation Structure of Sea Surface Winds." Journal of Climate 25, no. 19 (April 5, 2012): 6684–700. http://dx.doi.org/10.1175/jcli-d-11-00698.1.
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Abstract The temporal autocorrelation structures of sea surface vector winds and wind speeds are considered. Analyses of scatterometer and reanalysis wind data demonstrate that the autocorrelation functions (acf) of surface zonal wind, meridional wind, and wind speed generally drop off more rapidly in the midlatitudes than in the low latitudes. Furthermore, the meridional wind component and wind speed generally decorrelate more rapidly than the zonal wind component. The anisotropy in vector wind decorrelation scales is demonstrated to be most pronounced in the storm tracks and near the equator, and to be a feature of winds throughout the depth of the troposphere. The extratropical anisotropy is interpreted in terms of an idealized kinematic eddy model as resulting from differences in the structure of wind anomalies in the directions along and across eddy paths. The tropical anisotropy is interpreted in terms of the kinematics of large-scale equatorial waves and small-scale convection. Modeling the vector wind fluctuations as Gaussian, an explicit expression for the wind speed acf is obtained. This model predicts that the wind speed acf should decay more rapidly than that of at least one component of the vector winds. Furthermore, the model predicts a strong dependence of the wind speed acf on the ratios of the means of vector wind components to their standard deviations. These model results are shown to be broadly consistent with the relationship between the acf of vector wind components and wind speed, despite the presence of non-Gaussian structure in the observed surface vector winds.
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Monahan, Adam H. "Can We See the Wind? Statistical Downscaling of Historical Sea Surface Winds in the Subarctic Northeast Pacific." Journal of Climate 25, no. 5 (March 2012): 1511–28. http://dx.doi.org/10.1175/2011jcli4089.1.
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The statistical predictability of wintertime (December–February) monthly-mean sea surface winds (both vector wind components and wind speed) in the subarctic northeast Pacific off the west coast of Canada is considered, in the context of surface wind downscaling. Predictor fields (zonal wind, meridional wind, wind speed, and temperature) are shown to carry predictive information on the large scales (both vertical and horizontal) that are well simulated by numerical weather prediction and global climate models. It is found that, in general, the monthly mean vector wind components are more predictable by indices of the large-scale flow than by the monthly mean wind speed, with no systematic vertical variation in predictive skill for either across the depth of the troposphere. The difference in predictive skill between monthly-mean vector wind components and wind speed is interpreted in terms of an idealized model of the vector wind speed probability distribution, which demonstrates that for the conditions in the subarctic northeast Pacific, the sensitivity of mean wind speed to the standard deviations of vector wind component fluctuations (which are not well predicted) is greater than that to the mean vector wind components. It is demonstrated that this sensitivity is state dependent, and it is suggested that monthly mean wind speeds may be inherently more predictable in regions where the sensitivity to the vector wind component means is greater than that to the standard deviations. It is also demonstrated that daily wind fluctuations (both vector wind and wind speed) are generally more predictable than monthly-mean variability, and that monthly averages of the predicted daily winds generally represent the monthly-mean surface winds better than the predictions directly from monthly mean predictors.
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Bentamy, A., D. Croize-Fillon, and C. Perigaud. "Characterization of ASCAT measurements based on buoy and QuikSCAT wind vector observations." Ocean Science 4, no. 4 (December 11, 2008): 265–74. http://dx.doi.org/10.5194/os-4-265-2008.
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Abstract. The new scatterometer Advanced SCATterometer (ASCAT) onboard MetOp-A satellite provides surface wind speed and direction over global ocean with a spatial resolution of 25 km square over two swaths of 550 km widths. The accuracy of ASCAT wind retrievals is determined through various comparisons with moored buoys. The comparisons indicate that the remotely sensed wind speeds and directions agree well with buoy data. The root-mean-squared differences of the wind speed and direction are less than 1.72 m/s and 18°, respectively. At global scale, ASCAT winds are compared with surface winds derived from QuikSCAT scatterometer. The results confirm the buoy analyses, especially for wind speed ranging between 3 m/s and 20 m/s. For higher wind conditions, ASCAT is biased low. The ASCAT underestimation with respect to QuikSCAT winds is wind speed dependent. The comparisons based on the collocated scatterometer data collected after 17 of October 2007 indicate that there are significant improvements compared to previous periods.
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Bentamy, A. "Characterization of ASCAT measurements based on buoy and QuikSCAT wind vector observations." Ocean Science Discussions 5, no. 1 (March 19, 2008): 77–101. http://dx.doi.org/10.5194/osd-5-77-2008.
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Abstract. The new scatterometer Advanced SCATterometer (ASCAT) onboard MetOp-A satellite provides surface wind speed and direction over global ocean with a spatial resolution of 25 km square over two swaths of 550 km widths. The accuracy of ASCAT wind retrievals is determined through various comparisons with moored buoys. The comparisons indicate that the remotely sensed wind speeds and directions agree well with buoy data. The root-mean-squared differences of the wind speed and direction are less than 1.72 m/s and 18°, respectively. At global scale, ASCAT winds are compared with surface winds derived from QuikSCAT scatterometer. The results confirm the buoy analyses, especially for wind speed ranging between 3 m/s and 20 m/s. For higher wind conditions, ASCAT is biased low. The ASCAT underestimation with respect to QuikSCAT winds is wind speed dependent. The comparisons based on the collocated scatterometer data collected after 17 October 2007 indicate that there are significant improvements compared to previous periods.
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Dong, Zhounan, and Shuanggen Jin. "Evaluation of Spaceborne GNSS-R Retrieved Ocean Surface Wind Speed with Multiple Datasets." Remote Sensing 11, no. 23 (November 22, 2019): 2747. http://dx.doi.org/10.3390/rs11232747.
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Spaceborne Global Navigation Satellite Systems-Reflectometry (GNSS-R) can estimate the geophysical parameters by receiving Earth’s surface reflected signals. The CYclone Global Navigation Satellite System (CYGNSS) mission with eight microsatellites launched by NASA in December 2016, which provides an unprecedented opportunity to rapidly acquire ocean surface wind speed globally. In this paper, a refined spaceborne GNSS-R sea surface wind speed retrieval algorithm is presented and validated with the ground surface reference wind speed from numerical weather prediction (NWP) and cross-calibrated multi-platform ocean surface wind vector analysis product (CCMP), respectively. The results show that when the wind speed was less than 20 m/s, the RMS of the GNSS-R retrieved wind could achieve 1.84 m/s in the case where the NWP winds were used as the ground truth winds, while the result was better than the NWP-based retrieved wind speed with an RMS of 1.68 m/s when the CCMP winds were used. The two sets of inversion results were further evaluated by the buoy winds, and the uncertainties from the NWP-derived and CCMP-derived model prediction wind speed were 1.91 m/s and 1.87 m/s, respectively. The accuracy of inversed wind speeds for different GNSS pseudo-random noise (PRN) satellites and types was also analyzed and presented, which showed similar for different PRN satellites and different types of satellites.
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Butler, Bret, Steve Quarles, Christine Standohar-Alfano, Murray Morrison, Daniel Jimenez, Paul Sopko, Cyle Wold, et al. "Exploring fire response to high wind speeds: fire rate of spread, energy release and flame residence time from fires burned in pine needle beds under winds up to 27 ms−1." International Journal of Wildland Fire 29, no. 1 (2020): 81. http://dx.doi.org/10.1071/wf18216.
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The relationship between wildland fire spread rate and wind has been a topic of study for over a century, but few laboratory studies report measurements in controlled winds exceeding 5ms−1. In this study, measurements of fire rate of spread, flame residence time and energy release are reported for fires burning under controlled atmospheric conditions in shallow beds of pine needles subject to winds ranging from 0 to 27ms−1 (measured 5m above ground level). The data suggested that under constant flow conditions when winds are less than 10ms−1, fire rate of spread increases linearly at a rate of ~3% of the wind speed, which generally agrees with other laboratory-based models. When wind speed exceeds 10ms−1, the fire rate of spread response to wind remains linear but with a much stronger dependence, spreading at a rate of ~13% of the wind speed. Radiative and convective heating correlated directly to wind speed, with radiant heating increasing approximately three-fold as much as convective heating over the range of winds explored. The data suggested that residence time is inversely related to wind speed and appeared to approach a lower limit of ~20s as wind exceeded 15ms−1. Average flame residence time over the range of wind speeds was nominally 26s.
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van Zadelhoff, G. J., A. Stoffelen, P. W. Vachon, J. Wolfe, J. Horstmann, and M. Belmonte Rivas. "Retrieving hurricane wind speeds using cross-polarization C-band measurements." Atmospheric Measurement Techniques 7, no. 2 (February 7, 2014): 437–49. http://dx.doi.org/10.5194/amt-7-437-2014.
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Abstract. Hurricane-force wind speeds can have a large societal impact and in this paper microwave C-band cross-polarized (VH) signals are investigated to assess if they can be used to derive extreme wind-speed conditions. European satellite scatterometers have excellent hurricane penetration capability at C-band, but the vertically (VV) polarized signals become insensitive above 25 m s−1. VV and VH polarized backscatter signals from RADARSAT-2 SAR imagery acquired during severe hurricane events were compared to collocated SFMR wind measurements acquired by NOAA's hurricane-hunter aircraft. From this data set a geophysical model function (GMF) at strong-to-extreme/severe wind speeds (i.e., 20 m s−1 < U10 < 45 m s−1) is derived. Within this wind speed regime, cross-polarized data showed no distinguishable loss of sensitivity and as such, cross-polarized data can be considered a good candidate for the retrieval of strong-to-severe wind speeds from satellite instruments. The upper limit of 45 m s−1 is defined by the currently available collocated data. The validity of the derived relationship between wind speed and VH backscatter has been evaluated by comparing the cross-polarized signals to two independent wind-speed data sets (i.e., short-range ECMWF numerical weather prediction (NWP) model forecast winds and the NOAA best estimate 1-minute maximum sustained winds). Analysis of the three comparison data sets confirm that cross-polarized signals from satellites will enable the retrieval of strong-to-severe wind speeds where VV or horizontal (HH) polarization data has saturated. The VH backscatter increases exponentially with respect to wind speed (linear against VH [dB]) and a near-real-time assessment of maximum sustained wind speed is possible using VH measurements. VH measurements thus would be an extremely valuable complement on next-generation scatterometers for hurricane forecast warnings and hurricane model initialization.
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Warrick, Douglas R., Tyson L. Hedrick, Andrew A. Biewener, Kristen E. Crandell, and Bret W. Tobalske. "Foraging at the edge of the world: low-altitude, high-speed manoeuvering in barn swallows." Philosophical Transactions of the Royal Society B: Biological Sciences 371, no. 1704 (September 26, 2016): 20150391. http://dx.doi.org/10.1098/rstb.2015.0391.
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While prior studies of swallow manoeuvering have focused on slow-speed flight and obstacle avoidance in still air, swallows survive by foraging at high speeds in windy environments. Recent advances in field-portable, high-speed video systems, coupled with precise anemometry, permit measures of high-speed aerial performance of birds in a natural state. We undertook the present study to test: (i) the manner in which barn swallows ( Hirundo rustica ) may exploit wind dynamics and ground effect while foraging and (ii) the relative importance of flapping versus gliding for accomplishing high-speed manoeuvers. Using multi-camera videography synchronized with wind-velocity measurements, we tracked coursing manoeuvers in pursuit of prey. Wind speed averaged 1.3–2.0 m s −1 across the atmospheric boundary layer, exhibiting a shear gradient greater than expected, with instantaneous speeds of 0.02–6.1 m s −1 . While barn swallows tended to flap throughout turns, they exhibited reduced wingbeat frequency, relying on glides and partial bounds during maximal manoeuvers. Further, the birds capitalized on the near-earth wind speed gradient to gain kinetic and potential energy during both flapping and gliding turns; providing evidence that such behaviour is not limited to large, fixed-wing soaring seabirds and that exploitation of wind gradients by small aerial insectivores may be a significant aspect of their aeroecology. This article is part of the themed issue ‘Moving in a moving medium: new perspectives on flight'.
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K, Suja. "Extracting Maximum Power from Wind Turbine Using Tip Speed Ratio and PO Algorithms by Limiting the Wind Speed." Revista Gestão Inovação e Tecnologias 11, no. 4 (July 10, 2021): 1241–51. http://dx.doi.org/10.47059/revistageintec.v11i4.2183.
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Yohana, Eflita, MSK Tony Suryo U, Binawan Luhung, Mohamad Julian Reza, and M. Badruz Zaman. "Experimental Study of Wind Booster Addition for Savonius Vertical Wind Turbine of Two Blades Variations Using Low Wind Speed." E3S Web of Conferences 125 (2019): 14003. http://dx.doi.org/10.1051/e3sconf/201912514003.
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The Wind turbine is a tool used in Wind Energy Conversion System (WECS). The wind turbine produces electricity by converting wind energy into kinetic energy and spinning to produce electricity. Vertical Axis Wind Turbine (VAWT) is designed to produce electricity from winds at low speeds. Vertical wind turbines have 2 types, they are wind turbine Savonius and Darrieus. This research is to know the effect of addition wind booster to Savonius vertical wind turbine with the variation 2 blades and 3 blades. Calculation the power generated by wind turbine using energy analysis method using the concept of the first law of thermodynamics. The result obtained is the highest value of blade power in Savonius wind turbine without wind booster (16.5 ± 1.9) W at wind speed 7 m/s with a tip speed ratio of 1.00 ± 0.01. While wind turbine Savonius with wind booster has the highest power (26.3 ± 1.6) W when the wind speed of 7 m/s with a tip speed ratio of 1.26 ± 0.01. The average value of vertical wind turbine power increases Savonius after wind booster use of 56%.
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Fisher, C. M., G. S. Young, N. S. Winstead, and J. D. Haqq-Misra. "Comparison of Synthetic Aperture Radar–Derived Wind Speeds with Buoy Wind Speeds along the Mountainous Alaskan Coast." Journal of Applied Meteorology and Climatology 47, no. 5 (May 1, 2008): 1365–76. http://dx.doi.org/10.1175/2007jamc1716.1.
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Abstract Satellite-borne synthetic aperture radar (SAR) offers the potential for remotely sensing surface wind speed both over the open sea and in close proximity to the coast. The resolution improvement of SAR over scatterometers is of particular advantage near coasts. Thus, there is a need to verify the performance of SAR wind speed retrieval in coastal environments adjacent to very complex terrain and subject to strong synoptic forcing. Mountainous coasts present a challenge because the wind direction values required for SAR wind speed retrieval algorithms cannot be obtained from global model analyses with as much accuracy there as over the open ocean or adjacent to gentle coasts where most previous SAR accuracy studies have been conducted. The performance of SAR wind speed retrieval in this challenging environment is tested using a 7-yr dataset from the mountainous coast of the Gulf of Alaska. SAR-derived wind speeds are compared with direct measurements from three U.S. Navy Oceanographic Meteorological Automatic Device (NOMAD) buoys. Both of the commonly used SAR wind speed retrieval models, CMOD4 and CMOD5, were tested, as was the impact of correcting the buoy-derived wind speed profile for surface-layer stability. Both SAR wind speed retrieval models performed well although there was some wind speed–dependent bias. This may be either a SAR wind speed retrieval issue or a buoy issue because buoys can underestimate winds as wind speed and thus sea state increase. The full set of tests is performed twice, once using wind directions from the U.S. Navy Operational Global Atmospheric Prediction System (NOGAPS) model analyses and once using wind direction observations from the buoys themselves. It is concluded that useful wind speeds can be derived from SAR backscatter and global model wind directions even in proximity to mountainous coastlines.
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Zhao, Yufei, Jianping Li, Qiang Zhang, Xiaowei Jiang, and Aixia Feng. "Diurnal Variations in Surface Wind over the Tibetan Plateau." Atmosphere 10, no. 3 (March 2, 2019): 112. http://dx.doi.org/10.3390/atmos10030112.
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This study uses hourly surface wind direction and wind speed observations from 53 meteorological stations on the Tibetan Plateau (TP) (70–105° E, 25–45° N) between 1995 and 2017 to investigate diurnal variations in the surface wind. The results show large diurnal variations in surface wind on the TP. The minimum wind speed occurs in the morning and the maximum in the afternoon. In all four seasons, the prevailing meridional wind is a southerly, and this is typically evident for more than two-thirds of each day. However, in the mornings during December–February and September–November, this southerly wind is replaced by a northerly, but remains southerly in the afternoon. The TP shows remarkable regional characteristics with respect to diurnal variations in wind speed. In the eastern region, the minimum and maximum daily wind speeds occur about 1 h later than in the west. Among the 53 meteorological stations, 79% observed that it took less time for the minimum speed to rise to the maximum speed than for the maximum to drop to the minimum. The blocking effect of the high surrounding terrain causes the diurnal variations seen in the surface winds at the three stations in the Qaidam Basin to differ significantly from those observed at the other stations elsewhere on the plateau. These Qaidam Basin stations recorded their maximum wind speeds around noon, with the minimum at dusk, which is around 1900 LST. The EOF1 (EOF = empirical orthogonal function) of the hourly wind speed on the TP indicates the key daily circulation feature of the region; i.e., the wind speed is high in the afternoon and low in the morning. The EOF2 reflects the regional differences in the diurnal variations of wind speed on the TP; i.e., the eastern region reaches the daily maximum and minimum wind speeds slightly later than the western region.
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Bell, T. G., W. De Bruyn, S. D. Miller, B. Ward, K. Christensen, and E. S. Saltzman. "Air/sea DMS gas transfer in the North Atlantic: evidence for limited interfacial gas exchange at high wind speed." Atmospheric Chemistry and Physics Discussions 13, no. 5 (May 21, 2013): 13285–322. http://dx.doi.org/10.5194/acpd-13-13285-2013.
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Abstract. Shipboard measurements of eddy covariance DMS air/sea fluxes and seawater concentration were carried out in the North Atlantic bloom region in June/July 2011. Gas transfer coefficients (k660) show a linear dependence on mean horizontal wind speed at wind speeds up to 11 m s−1. At higher wind speeds the relationship between k660 and wind speed weakens. At high winds, measured DMS fluxes were lower than predicted based on the linear relationship between wind speed and interfacial stress extrapolated from low to intermediate wind speeds. In contrast, the transfer coefficient for sensible heat did not exhibit this effect. The apparent suppression of air/sea gas flux at higher wind speeds appears to be related to sea state, as determined from shipboard wave measurements. These observations are consistent with the idea that long waves suppress near surface water side turbulence, and decrease interfacial gas transfer. This effect may be more easily observed for DMS than for less soluble gases, such as CO2, because the air/sea exchange of DMS is controlled by interfacial rather than bubble-mediated gas transfer under high wind speed conditions.
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Bell, T. G., W. De Bruyn, S. D. Miller, B. Ward, K. H. Christensen, and E. S. Saltzman. "Air–sea dimethylsulfide (DMS) gas transfer in the North Atlantic: evidence for limited interfacial gas exchange at high wind speed." Atmospheric Chemistry and Physics 13, no. 21 (November 13, 2013): 11073–87. http://dx.doi.org/10.5194/acp-13-11073-2013.
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Abstract. Shipboard measurements of eddy covariance dimethylsulfide (DMS) air–sea fluxes and seawater concentration were carried out in the North Atlantic bloom region in June/July 2011. Gas transfer coefficients (k660) show a linear dependence on mean horizontal wind speed at wind speeds up to 11 m s−1. At higher wind speeds the relationship between k660 and wind speed weakens. At high winds, measured DMS fluxes were lower than predicted based on the linear relationship between wind speed and interfacial stress extrapolated from low to intermediate wind speeds. In contrast, the transfer coefficient for sensible heat did not exhibit this effect. The apparent suppression of air–sea gas flux at higher wind speeds appears to be related to sea state, as determined from shipboard wave measurements. These observations are consistent with the idea that long waves suppress near-surface water-side turbulence, and decrease interfacial gas transfer. This effect may be more easily observed for DMS than for less soluble gases, such as CO2, because the air–sea exchange of DMS is controlled by interfacial rather than bubble-mediated gas transfer under high wind speed conditions.
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Heard, Maurice C. "Wind speed measurement." Journal of the Acoustical Society of America 81, no. 6 (June 1987): 2001. http://dx.doi.org/10.1121/1.394734.
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Uhlhorn, Eric W., Peter G. Black, James L. Franklin, Mark Goodberlet, James Carswell, and Alan S. Goldstein. "Hurricane Surface Wind Measurements from an Operational Stepped Frequency Microwave Radiometer." Monthly Weather Review 135, no. 9 (September 1, 2007): 3070–85. http://dx.doi.org/10.1175/mwr3454.1.
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Abstract For the first time, the NOAA/Aircraft Operations Center (AOC) flew stepped frequency microwave radiometers (SFMRs) on both WP-3D research aircraft for operational hurricane surface wind speed measurement in 2005. An unprecedented number of major hurricanes provided ample data to evaluate both instrument performance and surface wind speed retrieval quality up to 70 m s−1 (Saffir–Simpson category 5). To this end, a new microwave emissivity–wind speed model function based on estimates of near-surface winds in hurricanes by global positioning system (GPS) dropwindsondes is proposed. For practical purposes, utilizing this function removes a previously documented high bias in moderate SFMR-measured wind speeds (10–50 m s−1), and additionally corrects an extreme wind speed (>60 m s−1) underestimate. The AOC operational SFMRs yield retrievals that are precise to within ∼2% at 30 m s−1, which is a factor of 2 improvement over the NOAA Hurricane Research Division’s SFMR, and comparable to the precision found here for GPS dropwindsonde near-surface wind speeds. A small (1.6 m s−1), but statistically significant, overall high bias was found for independent SFMR measurements utilizing emissivity data not used for model function development. Across the range of measured wind speeds (10–70 m s−1), SFMR 10-s averaged wind speeds are within 4 m s−1 (rms) of the dropwindsonde near-surface estimate, or 5%–25% depending on speed. However, an analysis of eyewall peak wind speeds indicates an overall 2.6 m s−1 GPS low bias relative to the peak SFMR estimate on the same flight leg, suggesting a real increase in the maximum wind speed estimate due to SFMR’s high-density sampling. Through a series of statistical tests, the SFMR is shown to reduce the overall bias in the peak surface wind speed estimate by ∼50% over the current flight-level wind reduction method and is comparable at extreme wind speeds. The updated model function is demonstrated to behave differently below and above the hurricane wind speed threshold (∼32 m s−1), which may have implications for air–sea momentum and kinetic energy exchange. The change in behavior is at least qualitatively consistent with recent laboratory and field results concerning the drag coefficient in high wind speed conditions, which show a fairly clear “leveling off” of the drag coefficient with increased wind speed above ∼30 m s−1. Finally, a composite analysis of historical data indicates that the earth-relative SFMR peak wind speed is typically located in the hurricane’s right-front quadrant, which is consistent with previous observational and theoretical studies of surface wind structure.
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Fang, He, Tao Xie, William Perrie, Guosheng Zhang, Jingsong Yang, and Yijun He. "Comparison of C-Band Quad-Polarization Synthetic Aperture Radar Wind Retrieval Models." Remote Sensing 10, no. 9 (September 11, 2018): 1448. http://dx.doi.org/10.3390/rs10091448.
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This work discusses the accuracy of C-2PO (C-band cross-polarized ocean backscatter) and CMOD4 (C-band model) geophysical model functions (GMF) for sea surface wind speed retrieval from satellite-born Synthetic Aperture Radar (SAR) images over in the Northwest Pacific off the coast of China. In situ observations are used for comparison of the retrieved wind speed using two established wind retrieval models: C-2PO model and CMOD4 GMF. Using 439 samples from 92 RADARSAT-2 fine quad-polarization SAR images and corresponding reference winds, we created two subset wind speed databases: the training and testing subsets. From the training data subset, we retrieve ocean surface wind speeds (OSWSs) from different models at each polarization and compare with reference wind speeds. The RMSEs of SAR-retrieved wind speeds are: 2.5 m/s: 2.11 m/s (VH-polarized), 2.13 m/s (HV-polarized), 1.86 m/s (VV-polarized) and 2.26 m/s (HH-polarized) and the correlation coefficients are 0.86 (VH-polarized), 0.85(HV-polarized), 0.87(VV-polarized) and 0.83 (HH-polarized), which are statistically significant at the 99.9% significance level. Moreover, we found that OSWSs retrieved using C-2PO model at VH-polarized are most suitable for moderate-to-high winds while CMOD4 GMF at VV-polarized tend to be best for low-to-moderate winds. A hybrid wind retrieval model is put forward composed of the two models, C-2PO and CMOD4 and sets of SAR test data are used in order to establish an appropriate wind speed threshold, to differentiate the wind speed range appropriate for one model from that of the other. The results show that the OSWSs retrieved using our hybrid method has RMSE of 1.66 m/s and the correlation coefficient are 0.9, thereby significantly outperforming both the C-2PO and CMOD4 models.
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Zhang, Lian Zhong, and Jing Min Li. "The Research of Composite Solar and Wind Energy Materials Generator." Advanced Materials Research 531 (June 2012): 584–88. http://dx.doi.org/10.4028/www.scientific.net/amr.531.584.
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Composite generator of solar and wind energy materials the generators， energy-saving environmental protection as a precondition to full use of green renewable energy, making wind power in weak wind conditions and strong winds can maintain normal operation of wind turbines how wind instability Under normal operation, but at higher wind speeds, the blades are not damaged? We start from the pressure-controlled device, the mechanical components and microelectronic technology combine to complete the slurry from the regulator controlled by changing the role of plasma from the body, strengthen the control of wind turbines, wind generators can adapt to changes in wind speed. In the initial wind speed easy to start; in the design of wind speed and wind speed between the initial access to higher wind energy utilization coefficient; In addition, the weak and the solar wind is sufficient,solar power can also get the power to add the function to ensure that the entire power system running smoothly, to achieve full power generation purposes.
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Zhang, Tiejun, Pengcheng Yan, Zhaorong Li, Yousheng Wang, and Yaohui Li. "Bias-correction method for wind-speed forecasting." Meteorologische Zeitschrift 28, no. 4 (November 21, 2019): 293–304. http://dx.doi.org/10.1127/metz/2019/0950.
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Cauchy, Pierre, Karen J. Heywood, Nathan D. Merchant, Bastien Y. Queste, and Pierre Testor. "Wind Speed Measured from Underwater Gliders Using Passive Acoustics." Journal of Atmospheric and Oceanic Technology 35, no. 12 (December 2018): 2305–21. http://dx.doi.org/10.1175/jtech-d-17-0209.1.
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AbstractWind speed measurements are needed to understand ocean–atmosphere coupling processes and their effects on climate. Satellite observations provide sufficient spatial and temporal coverage but are lacking adequate calibration, while ship- and mooring-based observations are spatially limited and have technical shortcomings. However, wind-generated underwater noise can be used to measure wind speed, a method known as Weather Observations Through Ambient Noise (WOTAN). Here, we adapt the WOTAN technique for application to ocean gliders, enabling calibrated wind speed measurements to be combined with contemporaneous oceanographic profiles over extended spatial and temporal scales. We demonstrate the methodology in three glider surveys in the Mediterranean Sea during winter 2012/13. Wind speeds ranged from 2 to 21.5 m s−1, and the relationship to underwater ambient noise measured from the glider was quantified. A two-regime linear model is proposed, which validates a previous linear model for light winds (below 12 m s−1) and identifies a regime change in the noise generation mechanism at higher wind speeds. This proposed model improves on previous work by extending the validated model range to strong winds of up to 21.5 m s−1. The acquisition, data processing, and calibration steps are described. Future applications for glider-based wind speed observations and the development of a global wind speed estimation model are discussed.
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WEERASINGHE, R. M., A. S. PANNILA, M. K. JAYANANDA, and D. U. J. SONNADARA. "MULTIFRACTAL BEHAVIOR OF WIND SPEED AND WIND DIRECTION." Fractals 24, no. 01 (March 2016): 1650003. http://dx.doi.org/10.1142/s0218348x16500031.
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In this paper, an analysis of temporal variation of wind speed and wind direction recorded at 10 min intervals are presented. The measurements were carried out at Hambanthota, a site located in the southern coastal belt of Sri Lanka which has a high potential for wind power generation. The multifractal detrended fluctuation analysis was used to analyze the temporal scaling properties of wind speeds and wind directions. The analysis was carried out for seasonal variation of wind speed and wind direction. It was observed that the scaling behavior of wind speed in Hambanthota is similar to the scaling behavior observed in previous studies which were carried out in other parts of the world. The seasonal wind and wind direction change exhibits different scaling behavior. No difference in scaling behavior was observed with heights. The degree of multifractality is high for wind direction when compared with wind speed for each season.
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Liu, Hong Peng, Xiao Di Zhang, Hong Sheng Li, and Qing Wang. "Wind Speed Forecasting in Wind Farm." Applied Mechanics and Materials 672-674 (October 2014): 306–9. http://dx.doi.org/10.4028/www.scientific.net/amm.672-674.306.
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Artificial neural network method was used to forecast the wind speed, and two wind speed forecasting models were built based on BP and RBF neural network methods. 24 hours continuous wind speed forecast was conducted for a single wind turbine in wind farm. The results show that the models built are reasonable and have high prediction accuracy. By comparing the two kinds of wind speed forecasting models, BP neural network forecasting model has higher prediction accuracy than RBF neural network forecasting model in wind speed, but it demands much more training time.
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Lawrence, W., D. Langridge, and D. Johnston. "Low wind speed wind generation scheme." Renewable Energy 4, no. 5 (July 1994): 489–94. http://dx.doi.org/10.1016/0960-1481(94)90211-9.
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Nissen, J. N., and S. E. Gryning. "Seasonality in onshore normalized wind profiles above the surface layer." Advances in Science and Research 4, no. 1 (May 12, 2010): 57–62. http://dx.doi.org/10.5194/asr-4-57-2010.
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Abstract. This work aims to study the seasonal difference in normalized wind speed above the surface layer as it is observed at the 160 m high mast at the coastal site Høvsøre at winds from the sea (westerly). Normalized and stability averaged wind speeds above the surface layer are observed to be 20 to 50% larger in the winter/spring seasons compared to the summer/autumn seasons at winds from west within the same atmospheric stability class. A method combining the mesoscale model, COAMPS, and observations of the surface stability of the marine boundary layer is presented. The objective of the method is to reconstruct the seasonal signal in normalized wind speed and identify the physical process behind. The method proved reasonably successful in capturing the relative difference in wind speed between seasons, indicating that the simulated physical processes are likely candidates to the observed seasonal signal in normalized wind speed.
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Fu, Zhaokun, and Qingwen Li. "Study on Wind-Proof Effect and Stability of Windbreak Fence in Alpine Skiing Center." Sustainability 15, no. 4 (February 12, 2023): 3369. http://dx.doi.org/10.3390/su15043369.
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As a venue for the 2022 Winter Olympic and Paralympic Games, the National Alpine Skiing Center is located on Xiaohaitou Mountain in Beijing’s Yanqing district, where strong winds occur frequently. To reduce the impact of strong winds on the competition, windbreak fences have been installed in the ski area. To determine the effect and stability of the windbreak fences beside the ski slope of the alpine skiing center, the numerical simulation method was used to study the performance of 3.7 m, 4.7 m and 7.9 m high wind barriers. According to the actual meteorological conditions, two kinds of inlet wind speeds of 10 m/s and 33 m/s were set. The results show that the ambient wind speed is maximum only in a small area near the opening through the windbreak fence. When the ambient wind speed is 10 and 33 m/s, the wind speed in most drainage areas behind the barrier is below 5 and 15 m/s, respectively, which is significantly lower than the wind speed of incoming flow, and the wind protection effect is obvious. When the wind speed at the entrance height is 10 m and 33 m/s, the wind-proof effect is obvious. The wind-proof effect of 7.9 m high windproof bars is better than that of 3.7 and 4.7 m high windproof bars. The wind pressure at the top of the fence is the highest, and the wind pressure also increases when the wind speed increases. Under the action of maximum wind speed, the stability of a 7.9 m high storm fence is low.
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Fan, Wenxin, Yi Liu, Adrian Chappell, Li Dong, Rongrong Xu, Marie Ekström, Tzung-May Fu, and Zhenzhong Zeng. "Evaluation of Global Reanalysis Land Surface Wind Speed Trends to Support Wind Energy Development Using In Situ Observations." Journal of Applied Meteorology and Climatology 60, no. 1 (January 2021): 33–50. http://dx.doi.org/10.1175/jamc-d-20-0037.1.
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AbstractGlobal reanalysis products are important tools across disciplines to study past meteorological changes and are especially useful for wind energy resource evaluations. Studies of observed wind speed show that land surface wind speed declined globally since the 1960s (known as global terrestrial stilling) but reversed with a turning point around 2010. Whether the declining trend and the turning point have been captured by reanalysis products remains unknown so far. To fill this research gap, a systematic assessment of climatological winds and trends in five reanalysis products (ERA5, ERA-Interim, MERRA-2, JRA-55, and CFSv2) was conducted by comparing gridcell time series of 10-m wind speed with observational data from 1439 in situ meteorological stations for the period 1989–2018. Overall, ERA5 is the closest to the observations according to the evaluation of climatological winds. However, substantial discrepancies were found between observations and simulated wind speeds. No reanalysis product showed similar change to that of the global observations, although some showed regional agreement. This discrepancy between observed and reanalysis land surface wind speed indicates the need for prudence when using reanalysis products for the evaluation and prediction of winds. The possible reasons for the inconsistent wind speed trends between reanalysis products and observations are analyzed. The results show that wind energy production should select different products for different regions to minimize the discrepancy with observations.
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Kodama, Yuji, Gerd Wendler, and Joan Gosink. "The Effect of Blowing Snow on Katabatic Winds in Antarctica." Annals of Glaciology 6 (1985): 59–62. http://dx.doi.org/10.3189/1985aog6-1-59-62.
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An acceleration of the katabatic winds during periods of blowing snow was observed in Adelie Land, Antarctica. Data collected by Automatic Weather Stations' (AWS) showed a change in the relationship between the katabatic term of the surface geostrophic wind (katabatic force) and the wind speed for periods of blowing snow. When measurements of the katabatic force were plotted against the cube of the wind speed, the slope was steeper for wind speeds at less than a threshold speed for blowing snow. The difference between these two slopes was partly explained by the effect of blowing snow entrained into the atmospheric boundary layer.
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Kodama, Yuji, Gerd Wendler, and Joan Gosink. "The Effect of Blowing Snow on Katabatic Winds in Antarctica." Annals of Glaciology 6 (1985): 59–62. http://dx.doi.org/10.1017/s026030550000999x.
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An acceleration of the katabatic winds during periods of blowing snow was observed in Adelie Land, Antarctica. Data collected by Automatic Weather Stations' (AWS) showed a change in the relationship between the katabatic term of the surface geostrophic wind (katabatic force) and the wind speed for periods of blowing snow. When measurements of the katabatic force were plotted against the cube of the wind speed, the slope was steeper for wind speeds at less than a threshold speed for blowing snow. The difference between these two slopes was partly explained by the effect of blowing snow entrained into the atmospheric boundary layer.
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Nasir Salim Hassen and Nor Azwadi Che Sidik. "Nozzle Type and Driving Speed Effects on Spray Density of Aerial Application According to the Wind Tunnel Measurements." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 84, no. 1 (July 1, 2021): 101–10. http://dx.doi.org/10.37934/arfmts.84.1.101110.
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Spray density (Number of droplets/cm2) is an important component of agricultural spraying processes. In the field, assessment of the spray density under effect of a number of variables such as nozzle type and driving speed without take in account the effect of cross wind speed is insufficient. In this study, to simulate field spray operation, tests were carried out in wind tunnel using automatic spraying mechanism to investigate and to clarify effect of three types of flat fan nozzle tip spray at three driving speeds under effect three cross wind speeds on spray density. Water sensitive papers (WSPs) were used to collect spray density data. Spray density was calculated through image processing program software. Performance of spray nozzles was validated relative to experimental data of a TP11003 reference nozzle. Results indicated that XR11003 nozzle behavior was to some extent similar to that TP11003 nozzle under effect slow wind speed. It is also noticed that the spray density value decreased with increasing driving speed and wind speed, the spray density value with driving speed of 2.2 m/s and wind speed of 1 m/s was the best, reaching 64.3 droplet /cm2. While the spray density value with driving speed of 5.5 m/s and wind speed of 3 m/s was the least, reaching 3.8 droplet /cm2. The current study presents that the use of DG11003 nozzle gives the best control spray density data under effect very windy conditions to the reference nozzle.
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Atabiq, Fauzun, Budiana Budiana, Arif Febriansyah Juwito, Irfan Syahri, and Ihsan Saputra. "MODIFICATION OF TWO POLES SINGLE PHASE INDUCTION MOTOR AS WIND PICO GENERATOR." JURNAL INTEGRASI 11, no. 1 (April 1, 2019): 68–73. http://dx.doi.org/10.30871/ji.v11i2.1132.
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As an alternative energy, the potential of wind power in Indonesia is quite high. Some of the constraints of wind power include the presence of intermittent winds, the average wind speed in the Indonesian is relatively low, or only certain areas that have moderate to high wind speeds, so that winds that are not too tight can cause the turbines not spinning. This study is about modifying a two pole single phase induction motor as a wind pico generator. Modifications made to the squirrel cage rotor induction motor become two poles axial flux permanent magnet rotors. The test results show that a two pole pico generator is not suitable to be applied to wind power units. Electric power produced by high-speed prime mover, above 1000 rpm only 2.53 Watts. Whereas when it is operated at low speed, less than 200 rpm, the maximum output power power only 44 mW.
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Bessho, Kotaro, Mark DeMaria, and John A. Knaff. "Tropical Cyclone Wind Retrievals from the Advanced Microwave Sounding Unit: Application to Surface Wind Analysis." Journal of Applied Meteorology and Climatology 45, no. 3 (March 1, 2006): 399–415. http://dx.doi.org/10.1175/jam2352.1.
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Abstract Horizontal winds at 850 hPa from tropical cyclones retrieved using the nonlinear balance equation, where the mass field was determined from Advanced Microwave Sounding Unit (AMSU) temperature soundings, are compared with the surface wind fields derived from NASA's Quick Scatterometer (QuikSCAT) and Hurricane Research Division H*Wind analyses. It was found that the AMSU-derived wind speeds at 850 hPa have linear relations with the surface wind speeds from QuikSCAT or H*Wind. There are also characteristic biases of wind direction between AMSU and QuikSCAT or H*Wind. Using this information to adjust the speed and correct for the directional bias, a new algorithm was developed for estimation of the tropical cyclone surface wind field from the AMSU-derived 850-hPa winds. The algorithm was evaluated in two independent cases from Hurricanes Floyd (1999) and Michelle (2001), which were observed simultaneously by AMSU, QuikSCAT, and H*Wind. In this evaluation the AMSU adjustment algorithm for wind speed worked well. Results also showed that the bias correction algorithm for wind direction has room for improvement.
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MADAN, O. P., N. NATARAJAN, H. C. SINGHAL, S. CHATURVEDI, and V. THIYAGARAJAN. "Surface wind at Leh." MAUSAM 43, no. 2 (December 30, 2021): 155–62. http://dx.doi.org/10.54302/mausam.v43i2.3365.
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Leh airfield normally experiences gale speed surface winds during the period from April to October. From November to March, the winds are relatively weak. The reason for the gale strength speed appears to be the channelling effect. Katabatlc /anabatic flows or Foehn effects do not appear to be the significant contributory factors. There are numerous points along the river Indus where similar gale strength speeds are encountered and hence these appear to be good wind energy prospecting potential sites.
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Rosen, M., and A. Hedenstrom. "Gliding flight in a jackdaw: a wind tunnel study." Journal of Experimental Biology 204, no. 6 (March 15, 2001): 1153–66. http://dx.doi.org/10.1242/jeb.204.6.1153.
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We examined the gliding flight performance of a jackdaw Corvus monedula in a wind tunnel. The jackdaw was able to glide steadily at speeds between 6 and 11 m s(−1). The bird changed its wingspan and wing area over this speed range, and we measured the so-called glide super-polar, which is the envelope of fixed-wing glide polars over a range of forward speeds and sinking speeds. The glide super-polar was an inverted U-shape with a minimum sinking speed (V(ms)) at 7.4 m s(−1) and a speed for best glide (V(bg)) at 8.3 m s(−)). At the minimum sinking speed, the associated vertical sinking speed was 0.62 m s(−1). The relationship between the ratio of lift to drag (L:D) and airspeed showed an inverted U-shape with a maximum of 12.6 at 8.5 m s(−1). Wingspan decreased linearly with speed over the whole speed range investigated. The tail was spread extensively at low and moderate speeds; at speeds between 6 and 9 m s(−1), the tail area decreased linearly with speed, and at speeds above 9 m s(−1) the tail was fully furled. Reynolds number calculated with the mean chord as the reference length ranged from 38 000 to 76 000 over the speed range 6–11 m s(−1). Comparisons of the jackdaw flight performance were made with existing theory of gliding flight. We also re-analysed data on span ratios with respect to speed in two other bird species previously studied in wind tunnels. These data indicate that an equation for calculating the span ratio, which minimises the sum of induced and profile drag, does not predict the actual span ratios observed in these birds. We derive an alternative equation on the basis of the observed span ratios for calculating wingspan and wing area with respect to forward speed in gliding birds from information about body mass, maximum wingspan, maximum wing area and maximum coefficient of lift. These alternative equations can be used in combination with any model of gliding flight where wing area and wingspan are considered to calculate sinking rate with respect to forward speed.
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Ruzicka, Rebekah E., and Michael R. Conover. "Influence of Wind and Humidity on Foraging Behavior of Olfactory Mesopredators." Canadian Field-Naturalist 125, no. 2 (April 1, 2011): 132. http://dx.doi.org/10.22621/cfn.v125i2.1196.
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Many mammalian predators rely on scents to locate prey and weather conditions that affect an odor plume (i.e., scents suspended in air) or depositional odor (i.e., scents laid on the ground) should affect predator foraging behavior. We predicted that wind speed, wind direction, and humidity would influence the foraging behavior of olfactory mesopredators. We tested these predictions by conducting spotlight surveys for foraging Red Foxes (Vulpes vulpes), Striped Skunks (Mephitis mephitis), and Raccoons (Procyon lotor) along the dike surrounding Willard Bay Reservoir in Willard, Utah, from August 2008 to August 2009. We recorded predator species, locations, numbers, and weather conditions at the time each predator was observed. While humidity had no effect on foraging, wind speed and direction were significant predictors of a predator's nightly foraging activity, with most predators observed when wind speeds were 2 to 4 m/s and winds were blowing perpendicularly over the dike the dike rather than parallel to the dike. Wind speed and direction also influenced where predators foraged on the dike, with predators being more likely to forage on the windward side of the dike when wind speeds were high enough to cause turbulence. We detected differences among predator species in their response to wind speed: Raccoons were more active than Striped Skunks and Red Foxes when the wind was calm and blowing parallel to the dike. Overall, our results indicate that these predator species alter their foraging behavior based on wind speed and wind direction. By foraging when winds were light and blowing perpendicularly over the dike, predators could likely enhance their ability to locate food using olfaction.
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Li, Dan-Yong, Wen-Chuan Cai, Peng Li, Zi-Jun Jia, Hou-Jin Chen, and Yong-Duan Song. "Neuroadaptive Variable Speed Control of Wind Turbine With Wind Speed Estimation." IEEE Transactions on Industrial Electronics 63, no. 12 (December 2016): 7754–64. http://dx.doi.org/10.1109/tie.2016.2591900.
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Zhang, Yagang, Shuang Gao, Jingyi Han, and Minghui Ban. "Wind Speed Prediction Research Considering Wind Speed Ramp and Residual Distribution." IEEE Access 7 (2019): 131873–87. http://dx.doi.org/10.1109/access.2019.2940897.
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Barambones, Oscar. "Robust Wind Speed Estimation and Control of Variable Speed Wind Turbines." Asian Journal of Control 21, no. 2 (April 19, 2018): 856–67. http://dx.doi.org/10.1002/asjc.1779.
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Eide, Siri Sofie, John Bjørnar Bremnes, and Ingelin Steinsland. "Bayesian Model Averaging for Wind Speed Ensemble Forecasts Using Wind Speed and Direction." Weather and Forecasting 32, no. 6 (December 1, 2017): 2217–27. http://dx.doi.org/10.1175/waf-d-17-0091.1.
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Abstract In this paper, probabilistic wind speed forecasts are constructed based on ensemble numerical weather prediction (NWP) forecasts for both wind speed and wind direction. Including other NWP variables in addition to the one subject to forecasting is common for statistical calibration of deterministic forecasts. However, this practice is rarely seen for ensemble forecasts, probably because of a lack of methods. A Bayesian modeling approach (BMA) is adopted, and a flexible model class based on splines is introduced for the mean model. The spline model allows both wind speed and wind direction to be included nonlinearly. The proposed methodology is tested for forecasting hourly maximum 10-min wind speeds based on ensemble forecasts from the European Centre for Medium-Range Weather Forecasts at 204 locations in Norway for lead times from +12 to +108 h. An improvement in the continuous ranked probability score is seen for approximately 85% of the locations using the proposed method compared to standard BMA based on only wind speed forecasts. For moderate-to-strong wind the improvement is substantial, while for low wind speeds there is generally less or no improvement. On average, the improvement is 5%. The proposed methodology can be extended to include more NWP variables in the calibration and can also be applied to other variables.
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Obermann, Anika, Benedikt Edelmann, and Bodo Ahrens. "Influence of sea surface roughness length parameterization on Mistral and Tramontane simulations." Advances in Science and Research 13 (July 8, 2016): 107–12. http://dx.doi.org/10.5194/asr-13-107-2016.
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Abstract. The Mistral and Tramontane are mesoscale winds in southern France and above the Western Mediterranean Sea. They are phenomena well suited for studying channeling effects as well as atmosphere–land/ocean processes. This sensitivity study deals with the influence of the sea surface roughness length parameterizations on simulated Mistral and Tramontane wind speed and wind direction. Several simulations with the regional climate model COSMO-CLM were performed for the year 2005 with varying values for the Charnock parameter α. Above the western Mediterranean area, the simulated wind speed and wind direction pattern on Mistral days changes depending on the parameterization used. Higher values of α lead to lower simulated wind speeds. In areas, where the simulated wind speed does not change much, a counterclockwise rotation of the simulated wind direction is observed.