Relevant bibliographies by topics / Wind spectra

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

Academic literature on the topic 'Wind spectra'

Author: Grafiati
Published: 4 June 2021
Last updated: 12 February 2022

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Journal articles on the topic "Wind spectra"

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Li, Qiang, Markus Rapp, Gunter Stober, and Ralph Latteck. "High-resolution vertical velocities and their power spectrum observed with the MAARSY radar – Part 1: frequency spectrum." Annales Geophysicae 36, no. 2 (April 3, 2018): 577–86. http://dx.doi.org/10.5194/angeo-36-577-2018.

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Abstract. The Middle Atmosphere Alomar Radar System (MAARSY) installed at the island of Andøya has been run for continuous probing of atmospheric winds in the upper troposphere and lower stratosphere (UTLS) region. In the current study, we present high-resolution wind measurements during the period between 2010 and 2013 with MAARSY. The spectral analysis applying the Lomb–Scargle periodogram method has been carried out to determine the frequency spectra of vertical wind velocity. From a total of 522 days of observations, the statistics of the spectral slope have been derived and show a dependence on the background wind conditions. It is a general feature that the observed spectra of vertical velocity during active periods (with wind velocity > 10 m s−1) are much steeper than during quiet periods (with wind velocity < 10 m s−1). The distribution of spectral slopes is roughly symmetric with a maximum at −5/3 during active periods, whereas a very asymmetric distribution with a maximum at around −1 is observed during quiet periods. The slope profiles along altitudes reveal a significant height dependence for both conditions, i.e., the spectra become shallower with increasing altitudes in the upper troposphere and maintain roughly a constant slope in the lower stratosphere. With both wind conditions considered together the general spectra are obtained and their slopes are compared with the background horizontal winds. The comparisons show that the observed spectra become steeper with increasing wind velocities under quiet conditions, approach a spectral slope of −5/3 at a wind velocity of 10 m s−1 and then roughly maintain this slope (−5/3) for even stronger winds. Our findings show an overall agreement with previous studies; furthermore, they provide a more complete climatology of frequency spectra of vertical wind velocities under different wind conditions. Keywords. Meteorology and atmospheric dynamics (turbulence; waves and tides)
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Reid, JS. "Observational evidence of the interaction of ocean wind-sea with swell." Marine and Freshwater Research 46, no. 2 (1995): 419. http://dx.doi.org/10.1071/mf9950419.

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More than 10 000 spectra of ocean wave data were acquired from a series of buoys moored in the Southern Ocean off the west coast of Tasmania for a period of seven years. Spectra were grouped according to the wind speed and whether the wind direction was onshore or offshore and the mean spectrum found for each group. The frequencies of the low frequency cut-offs and of the spectral peaks of the resulting mean spectra were found to be independent of the wind speed in contrast to self-similar standard spectra such as JONSWAP. This property is attributed to the presence of a swell background which controls the evolution of wind-seas in the open ocean. During offshore winds, the spectral variance between 0.04 Hz and 0.16 Hz was found to be negatively correlated with wind speed indicating that swell is in turn shaped either by the wind-sea or by the wind itself. Relationships between various spectral and time domain parameters and the wind speed were investigated empirically. The slope/acceleration measures such as m4, the spectral fourth moment, were found to be highly correlated with wind speed.
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Schafer, Robert, Susan K. Avery, Kenneth S. Gage, Paul E. Johnston, and D. A. Carter. "Improving Wind Profiler–Measured Winds Using Coplanar Spectral Averaging." Journal of Atmospheric and Oceanic Technology 21, no. 11 (November 1, 2004): 1671–78. http://dx.doi.org/10.1175/jtech1672.1.

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Abstract A method is presented that increases the detectability of weak clear-air signals by averaging Doppler spectra from coplanar wind profiler beams. The method, called coplanar spectral averaging (CSA), is applied to both simulated wind profiler spectra and to 1 yr of archived spectra from a UHF profiler at Christmas Island (1 October 1999–30 September 2000). A collocated 50-MHz wind profiler provides a truth for evaluating the CSA technique. In the absence of precipitation, it was found that CSA, when combined with a fuzzy logic quality control, increases the height coverage of the 1-hourly averaged UHF profiler winds by over 600 m (two range gates). CSA also increased the number of good wind estimates at each observation range by about 10%–25% over the standard consensus method.
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Jiang, Haoyu, and Lin Mu. "Wave Climate from Spectra and Its Connections with Local and Remote Wind Climate." Journal of Physical Oceanography 49, no. 2 (February 2019): 543–59. http://dx.doi.org/10.1175/jpo-d-18-0149.1.

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AbstractWind-generated waves can propagate over large distances. Therefore, wave spectra from a fixed point can record information about air–sea interactions in distant areas. In this study, the spectral wave climate for a point in the tropical eastern Pacific Ocean is computed. Several well-defined wave climate systems are observed in the mean wave spectrum. Significant seasonal cycling, long-term trends, and correlations with the Southern Oscillation, the Arctic Oscillation, and the Antarctic Oscillation are observed in the local wave spectra, showing abundant climatic information. Projections of wind vectors on the directions pointing to the target location are used to connect the spectral wave climate and basin-scale wind climate, because significant correlations are observed between the wave spectra and the wind projections of both local and remote wind systems. The origins of all the identified wave climate systems, including the westerlies and the trade winds in both hemispheres, are clearly shown in wind projection maps. Some of these origins are thousands of kilometers away from the target point, demonstrating the validity of this connection. Comparisons are made between wave spectra and the corresponding local and remote wind fields with respect to seasonal and interannual variability and long-term trends. The results show that each frequency and direction of ocean wave spectra at a certain location can be approximately linked to the wind field for a geographical area, implying that it is feasible to reconstruct spectral wave climates from observational wind field data and monitor wind climates from observational wave spectra geographically far away.
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Zhang, Shao Dong, Chun Ming Huang, Kai Ming Huang, Ye Hui Zhang, Yun Gong, and Quan Gan. "Vertical wavenumber spectra of three-dimensional winds revealed by radiosonde observations at midlatitude." Annales Geophysicae 35, no. 1 (January 13, 2017): 107–16. http://dx.doi.org/10.5194/angeo-35-107-2017.

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Abstract. By applying 12-year (1998–2009) radiosonde data over a midlatitude station, we studied the vertical wavenumber spectra of three-dimensional wind fluctuations. The horizontal wind spectra in the lower stratosphere coincide well with the well-known universal spectra, with mean spectral slopes of −2.91 ± 0.09 and −2.99 ± 0.09 for the zonal and meridional wind spectra, respectively, while the mean slopes in the troposphere are −2.64 ± 0.07 and −2.70 ± 0.06, respectively, which are systematically less negative than the canonical slope of −3. In both the troposphere and lower stratosphere, the spectral amplitudes (slopes) of the horizontal wind spectra are larger (less negative) in winter, and they are larger (less negative) in the troposphere than in the lower stratosphere. Moreover, we present the first statistical results of vertical wind fluctuation spectra, which revealed a very shallow spectral structure, with mean slopes of −0.58 ± 0.06 and −0.23 ± 0.05 in the troposphere and lower stratosphere, respectively. Such a shallow vertical wind fluctuation spectrum is considerably robust. Different from the horizontal wind spectrum, the slopes of the vertical wind spectra in both the troposphere and lower stratosphere are less negative in summer. The height variation of vertical wind spectrum amplitude is also different from that of the horizontal wind spectrum, with a larger amplitude in the lower stratosphere. These evident differences between the horizontal and vertical wind spectra strongly suggest they should obey different spectral laws. Quantitative comparisons with various theoretical models show that no existing spectral theories can comprehensively explain the observed three-dimensional wind spectra, indicating that the spectral features of atmospheric fluctuations are far from fully understood.
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Gille, Sarah T. "Statistical Characterization of Zonal and Meridional Ocean Wind Stress." Journal of Atmospheric and Oceanic Technology 22, no. 9 (September 1, 2005): 1353–72. http://dx.doi.org/10.1175/jtech1789.1.

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Abstract Four years of ocean vector wind data are used to evaluate statistics of wind stress over the ocean. Raw swath wind stresses derived from the Quick Scatterometer (QuikSCAT) are compared with five different global gridded wind products, including products based on scatterometer observations, meteorological analysis winds from the European Centre for Medium-Range Weather Forecasts, and reanalysis winds from the National Centers for Environmental Prediction. Buoy winds from a limited number of sites in the Pacific Ocean are also considered. Probability density functions (PDFs) computed for latitudinal bands show that mean wind stresses for the six global products are largely in agreement, while variances differ substantially, by a factor of 2 or more, with swath wind stresses indicating highest variances for meridional winds and for zonal winds outside the Tropics. Higher moments of the PDFs also differ. Kurtoses are large for all wind products, implying that PDFs are not Gaussian. None of the available gridded products fully captures the range of extreme wind events seen in the raw swath data. Frequency spectra for the five gridded products agree with frequency spectra from swath data at low frequencies, but spectral slopes differ at higher frequencies, particularly for frequencies greater than 100 cycles per year (cpy), which are poorly resolved by a single scatterometer. In the frequency range between 10 and 90 cpy that is resolved by the scatterometer, spectra derived from swath data are flatter than spectra from gridded products and are judged to be flatter than ω−2/3 at all latitudes.
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HARA, TETSU, and STEPHEN E. BELCHER. "Wind forcing in the equilibrium range of wind-wave spectra." Journal of Fluid Mechanics 470 (October 31, 2002): 223–45. http://dx.doi.org/10.1017/s0022112002001945.

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A new analytical model is developed for the equilibrium range of the spectrum of wind-forced ocean surface gravity waves. We first show that the existing model of Phillips (1985) does not satisfy overall momentum conservation at high winds. This constraint is satisfied by applying recent understanding of the wind forcing of waves. Waves exert a drag on the air flow so that they support a fraction of the applied wind stress, which thus leaves a smaller turbulent stress near the surface to force growth of shorter wavelength waves. Formulation of the momentum budget accounting for this sheltering constrains the overall conservation of momentum and leads to a local turbulent stress that reduces as the wavenumber increases. This local turbulent stress then forces wind-induced wave growth. Following Phillips (1985), the wind sea is taken to be a superposition of linear waves, and equilibrium is maintained by a balance between the three sources and sinks of wave action.These assumptions lead to analytical formulae for the local turbulent stress and the degree of saturation, B(k), of waves in the equilibrium range. We identify a sheltering wavenumber, ks, over which the local turbulent stress is significantly reduced by longer waves. At low wavenumbers or at low winds, when k [Lt ] ks, the sheltering is weak and B(k) has a similar form to the model of Phillips (1985). At higher wavenumbers or at higher winds, ks, B(k) makes a transition to being proportional to k0. The additional constraint of conservation of momentum also yields a formula for the coefficient that appears in the solution for B(k). The spectra for mature seas are calculated from the model and are shown to agree with field observations. In particular, our model predicts more realistic spectral levels toward the high wavenumber limit compared to the previous model of Phillips (1985).We suggest that the model may explain the overshoot phenomena observed in the spectral energy levels as the fetch increases.
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Hwang, Paul A., Yalin Fan, Francisco J. Ocampo-Torres, and Héctor García-Nava. "Ocean Surface Wave Spectra inside Tropical Cyclones." Journal of Physical Oceanography 47, no. 10 (October 2017): 2393–417. http://dx.doi.org/10.1175/jpo-d-17-0066.1.

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AbstractDirectional wave spectra acquired in hurricane reconnaissance missions are compared with wind-wave spectral models. The comparison result is quantified with two indices of model–measurement spectral agreement. In the main region of hurricane coverage, the indices vary sinusoidally with the azimuth angle referenced to the hurricane heading while showing a weak dependence on the radial distance from the hurricane center. The measured spectra agree well with three models evaluated in the back and right quarters, and they are underdeveloped in the front and left quarters. The local wind and wave directions also show a weak radial dependence and sinusoidal variation along the azimuth. The wind and wave vectors are almost collinear in the back and right quarters; they diverge azimuthally and become almost perpendicular in the left quarter. The azimuthally cyclical correlation between the indices of spectral agreement and the wind-wave directional difference is well described by the sinusoidal variations. Also discussed is the wide range of the spectral slopes observed in both hurricane and nonhurricane field data. It is unlikely that the observed spectral slope variation is caused by Doppler frequency shift from background currents. No clear correlation is found between spectral slope and various wind and wave parameters. The result suggests that the spectral slope needs to be treated as a stochastic random variable. Complementing the existing wind-wave spectral models that prescribe a fixed spectral slope of either −4 or −5, a general spectral model with its spectral parameters accommodating a variable spectral slope is introduced.
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Šafránková, J., Z. Němeček, F. Němec, L. Přech, A. Pitňa, C. H. K. Chen, and G. N. Zastenker. "SOLAR WIND DENSITY SPECTRA AROUND THE ION SPECTRAL BREAK." Astrophysical Journal 803, no. 2 (April 22, 2015): 107. http://dx.doi.org/10.1088/0004-637x/803/2/107.

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Sinha, Swati, Mary Lourde R., T. V. Chandrasekhar Sarma, J. S. Pillai, and Kushal R. Tuckley. "Spectral Feature-Based Classification of Wind Profiler Power Spectra." IEEE Transactions on Geoscience and Remote Sensing 56, no. 4 (April 2018): 2138–46. http://dx.doi.org/10.1109/tgrs.2017.2775654.

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Dissertations / Theses on the topic "Wind spectra"

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Won, Younsang. "Higher order numerical schemes for propagation of wind wave spectra." Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/39822.

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Boti, Ismael. "Noise spectra comparison among wind turbinesand its implications to human perception." Thesis, Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-25819.

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The noise coming from wind power development can be an environmental impact forthe surrounding communities. It is well known that the main wind turbine noise iscaused by the movement of the turbine wings through the air. However, there areuncertainties about the importance of machinery sounds and possible variations amongwind turbines. A high resolution acquisition system was used to perform a fieldexperiment comparison of the noise spectra from some wind turbines at Laholm(Sweden). The results have shown different band spectra peaks associated to machinerysounds among wind turbines from the same model and also from those of differentmanufactures. Maintenance conditions of these wind turbines could explain thedifferences in intensity and frequency locations of the band spectra peaks found. Inorder to know the importance for human audition of these peaks, listening test or doseresponsestudies would be needed to provide relevant information in this regard. Themethodology developed in this study is suggested to be useful for identifying certainmachinery failures which could corrupt the noise sounds emitted at certain wind turbinelocations.
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Campbell, P. R. J. "Toward DSS : intelligent prediction of wind spectra and mining of operational data." Thesis, University of Ulster, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.412521.

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Kawabata, Ryoji. "Accretion Flow and Wind around Compact Objects: Structure, Spectra, and Time Variations." 京都大学 (Kyoto University), 2010. http://hdl.handle.net/2433/120658.

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Huenemoerder, David, Lidia Oskinova, Richard Ignace, Wayne Waldron, Helge Todt, Kenji Hamaguchi, and Shunji Kitamoto. "On the Weak-Wind Problem in Massive Stars: X-Ray Spectra Reveal a Massive Hot Wind in mu Columbae." Digital Commons @ East Tennessee State University, 2012. https://dc.etsu.edu/etsu-works/6252.

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Mu Columbae is a prototypical weak-wind O star for which we have obtained a high-resolution X-ray spectrum with the Chandra LETG/ACIS instrument and a low-resolution spectrum with Suzaku. This allows us, for the first time, to investigate the role of X-rays on the wind structure in a bona fide weak-wind system and to determine whether there actually is a massive hot wind. The X-ray emission measure indicates that the outflow is an order of magnitude greater than that derived from UV lines and is commensurate with the nominal wind-luminosity relationship for O stars. Therefore, the "weak-wind problem"--identified from cool wind UV/optical spectra--is largely resolved by accounting for the hot wind seen in X-rays. From X-ray line profiles, Doppler shifts, and relative strengths, we find that this weak-wind star is typical of other late O dwarfs. The X-ray spectra do not suggest a magnetically confined plasma-the spectrum is soft and lines are broadened; Suzaku spectra confirm the lack of emission above 2 keV. Nor do the relative line shifts and widths suggest any wind decoupling by ions. The He-like triplets indicate that the bulk of the X-ray emission is formed rather close to the star, within five stellar radii. Our results challenge the idea that some OB stars are "weak-wind" stars that deviate from the standard wind-luminosity relationship. The wind is not weak, but it is hot and its bulk is only detectable in X-rays.
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Arnqvist, Johan. "Mean Wind and Turbulence Conditions in the Boundary Layer above Forests." Doctoral thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-237764.

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As wind turbines have grown, new installation areas become possible. Placing wind turbines in forested landscapes introduce uncertainties to the wind resource estimation. Even though close-to-canopy processes have been studied intensively during the last thirty years, the focus has mostly been on exchange processes and the height span of the studies has been below the rotor of a modern wind turbine. This thesis contains analysis of new measurements from a 138 m high tower in a forested landscape. The previous knowledge of near-canopy processes is extended to the region above the roughness sublayer. It is shown that above the roughness sublayer, the surface layer behaves as over low vegetation, and Monin-Obukhov similarity is shown to hold for several variables. However, in stable stratification, effects that could be linked to the boundary layer depth are shown to be present in the measurements. These include wind turning with height, the behaviour of the turbulence length scale and the curvature of the wind profile. Two new analytical models are presented in the thesis. One is a flux-profile expression in the roughness sublayer, which allows for analytical integration of the wind gradient. The model suggests that the roughness-sublayer effect depends on stratification and that the aerodynamic roughness length changes with stability. A decrease of roughness length in stable stratification is confirmed with a new method to determine the roughness length using measurements from the 138 m tower. The other model determines the spectral tensor in stable stratification using analytical solution to the rapid distortion equations for stratified shear flow, with homogeneous stratification and shear. By using a formulation for the integration time of the distortions of an isotropic spectrum, a model is derived which provides the cross spectra of velocity and temperature at any two given points in space. Finally the existence of waves in the wind over forests is investigated and it is concluded that the Kelvin-Helmholtz instability can create waves which are coherent in time and exist over the entire height span of wind turbine rotors. Linear wave theory is shown to be able to explain certain features of the waves.
Vindforsk III, Wind power in forests
Vindforsk IV, Forest wind
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Shan, Martin [Verfasser]. "Load Reducing Control for Wind Turbines: Load Estimation and Higher Level Controller Tuning based on Disturbance Spectra and Linear Models / Martin Shan." Kassel : Universitätsbibliothek Kassel, 2017. http://d-nb.info/1154972496/34.

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Ge, Zhongfu. "Analysis of surface pressure and velocity fluctuations in the flow over surface-mounted prisms." Diss., Virginia Tech, 2004. http://hdl.handle.net/10919/25965.

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The full-scale value of the Reynolds number associated with wind loads on structures is of the order of 10^7. This is further complicated by the high levels of turbulence fluctuations associated with strong winds. On the other hand, numerical and wind tunnel simulations are usually carried out at smaller values of Re. Consequently, the validation of these simulations should only be based on physical phenomena derived with tools capable of their identification. In this work, two physical aspects related to extreme wind loads on low-rise structures are examined. The first includes the statistical properties and prediction of pressure peaks. The second involves the identification of linear and nonlinear relations between pressure peaks and associated velocity fluctuations. The first part of this thesis is concerned with the statistical properties of surface pressure time series and their variations under different incident flow conditions. Various statistical tools, including space-time correlation, conditional sampling, the probability plot and the probability plot correlation coefficient, are used to characterize pressure peaks measured on the top surface of a surface-mounted prism. The results show that the Gamma distribution provides generally the best statistical description for the pressure time series, and that the method of moments is sufficient for determining its parameters. Additionally, the shape parameter of the Gamma distribution can be directly related to the incident flow conditions. As for prediction of pressure peaks, the results show that the probability of non-exceedence can best be derived from the Gumbel distribution. Two approaches for peak prediction, based on analysis of the parent pressure time series and of observed peaks, are presented. The prediction based on the parent time series yields more conservative estimates of the probability of non-exceedence. The second part of this thesis is concerned with determining the linear and nonlinear relations between pressure peaks and the velocity field. Validated by analytical test signals, the wavelet-based analysis is proven to be effective and accurate in detecting intermittent linear and nonlinear relations between the pressure and velocity fluctuations. In particular, intermittent linear and nonlinear velocity pressure relations are observed over the nondimensional frequency range fH/U<0.32. These results provide the basis for flow parameters and characteristics required in the simulation of the wind loads on structures.
Ph. D.
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Yilmaz, Nihal. "Spectral Characteristics Of Wind Waves In The Eastern Black Sea." Phd thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/3/12608614/index.pdf.

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Wind waves are highly complex, random phenomena. One way to describe the irregular nature of the sea surface is the use of wave energy spectrum. Spectral information for wind waves in the Black Sea is extremely limited. Knowledge on spectral characteristics of wind waves would contribute to scientific, engineering and operational coastal and marine activities in the Black Sea. The aim of the present thesis is to investigate characteristics of wind wave spectra for the Eastern Black Sea. This would allow detailed understanding of the nature of the waves occurring in this enclosed basin. Long-term wave measurements obtained by directional buoys deployed offshore at Sinop, Hopa and Gelendzhik were utilized as the three sets of wave data. Records were analyzed to identify them as uni-modal or multi-modal spectra, and occurrences of spectral peaks were computed. Single peaked spectra were studied as belonging to fully arisen or developing sea states. Model parameters of JONSWAP and PM spectra were estimated for the observed spectra by using a least square error method. The records of developing seas were further analyzed to select the ones belonging to stable wind conditions. Fetch dependencies of non-dimensional spectral variables, mean parameters of JONSWAP model spectrum and the envelop of dimensionless spectra were investigated for this data sub-set.
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Parra, Luis Antonio. "Sistema de controle com compensação de tempo morto aplicado à geração de vento em tanque de prova." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/3/3152/tde-22092014-155323/.

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Este trabalho descreve o desenvolvimento de um sistema de controle com compensação de tempo morto aplicado a um ventilador para simular os efeitos do vento em modelos de embarcações. O sistema é instalado no tanque de provas do Departamento de Engenharia Naval da Escola Politécnica da USP. Um sistema de controle baseado em computador é elaborado para a realização dos testes e validação, procedendo-se inicialmente a identificação do sistema a ser controlado. Na malha de controle, o sinal de referência é a velocidade do vento desejada em uma distância pré-definida do ventilador e pode ser tanto um valor constante (representando um vento constante) ou um valor variante no tempo (representando uma rajada de vento). O sistema atuador consiste de um inversor de frequência que aciona o ventilador e a velocidade do vento é medida por um anemômetro, cujo sinal é usado como realimentação para o controlador. A sintonia da malha é realizada pelo método do modelo interno (IMC) e o efeito do tempo morto é observado nos testes, aplicando-se o compensador baseado no Preditor de Smith para minimizá-lo. Pelos resultados dos ensaios, conclui-se que o Preditor de Smith melhora o desempenho do sistema de geração de vento.
This paper describes the development of a control system with dead time compensation applied to a fan to simulate wind effects in models of vessels. The system is installed on the academic towing tank of the Naval Architecture and Oceanic Engineering Department of the University of São Paulo. A control system based on computer is designed for testing and validation, proceeding initially to identify the system to be controlled. In the control loop, the set-point is the desired speed of the wind on a pre-defined distance from the fan and it can be either a constant value (representing a constant wind) or a time-varying value (representing a wind gust). The actuator system consists of a frequency-inverter that drives the fan and the wind speed is measured by an anemometer, whose signal is used as feedback to the controller. The tuning of the controller is made by the internal model control (IMC) and the effect of dead time is observed in the tests, applying the compensator based on Smith Predictor to minimize it. Through the results from the tests, it was concluded that the Smith Predictor improves the performance of the wind generation system.
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Books on the topic "Wind spectra"

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Gossard, Earl E. Automated editing of spectra from wind profilers. Boulder, Colo: U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, Environmental Research Laboratories, Environmental Technology Laboratory, 1997.

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Long, Charles E. Three-parameter characterization of shallow-water directional wind wave spectra. [Vicksburg, Miss: U.S. Army Engineer Waterways Experiment Station, 1994.

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Campbell, P. R. J. Towards DSS:intelligent prediction of wind spectra and mining of operational data. [S.l: The author], 2004.

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E, Long Charles. 1996 index of wind wave directional spectra measured at Harvest Platform. Vicksburg, Miss: U.S. Army Engineer Waterways Experiment Station, 1997.

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Long, Charles E. Directional wind wave characteristics at Harvest Platform. [Vicksburg, Miss: U.S. Army Engineer Waterways Experiment Station, 1995.

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E, Long Charles. 1994 annual index of wind wave directional spectra measured at Harvest Platform. [Vicksburg, Miss: U.S. Army Engineer Waterways Experiment Station, 1996.

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E, Long Charles. 1993 annual index of wind wave directional spectra measured at Harvest Platform. [Vicksburg, Miss: U.S. Army Engineer Waterways Experiment Station, 1995.

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E, Long Charles. 1994 annual index of wind wave directional spectra measured at Harvest Platform. [Vicksburg, Miss: U.S. Army Engineer Waterways Experiment Station, 1996.

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Barry, John Willard, and Patricia J. Skyler. Final report: Compendium of drop size spectra compiled from wind tunnel tests. Davis, CA: USDA Forest Service, Forest Pest Management, 1991.

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E, Long Charles. 1995 annual index of wind wave directional spectra measured at Harvest Platform. Vicksburg, Miss: U.S. Army Engineer Waterways Experiment Station, 1997.

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Book chapters on the topic "Wind spectra"

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Kitaigorodskii, S. A. "The Equilibrium Ranges in Wind—Wave Spectra." In Wave Dynamics and Radio Probing of the Ocean Surface, 9–40. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4684-8980-4_2.

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Kitaigorodskii, Sergei A. "The Dissipation Subrange of Wind Wave Spectra." In Breaking Waves, 199–206. Berlin, Heidelberg: Springer Berlin Heidelberg, 1992. http://dx.doi.org/10.1007/978-3-642-84847-6_20.

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Wolfe, A., R. D. Kelman, S. E. Warren, C. G. Maclennan, and L. J. Lanzerotti. "Hydromagnetic Frequency Spectra in the High Latitude Quiet Magnetosphere." In Solar Wind Sources of Magnetospheric Ultra-Low-Frequency Waves, 375–85. Washington, D. C.: American Geophysical Union, 2013. http://dx.doi.org/10.1029/gm081p0375.

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Thompson, D. R. "Calculation of Microwave Doppler Spectra from the Ocean Surface with a Time-Dependent Composite Model." In Radar Scattering from Modulated Wind Waves, 27–40. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-2309-6_3.

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Dexter, P. E., and S. Theodoridis. "Some Skywave Radar Measurements of Wind Vectors and Wave Spectra." In Wave Dynamics and Radio Probing of the Ocean Surface, 517–27. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4684-8980-4_36.

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Shonting, David, and Nancy Taylor. "On the Spectra of Wind Generated Sound in the Ocean." In Sea Surface Sound, 417–27. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-3017-9_30.

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Schühle, U., W. Curdt, K. Wilhelm, S. K. Solanki, and K. Stucki. "Signatures of Coronal Hole Spectra Between 660 Å and 1460 Å Measured with SUMER on SOHO." In Coronal Holes and Solar Wind Acceleration, 299–302. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-015-9167-6_49.

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Ramyakrishna, E., T. Narayana Rao, and N. Padmaja. "Development and Evaluation of Automated Algorithm for Estimation of Winds from Wind Profiler Spectra." In Advances in Intelligent Systems and Computing, 473–83. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-28658-7_40.

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Narita, Y., K. H. Glassmeier, S. P. Gary, M. L. Goldstein, and R. A. Treumann. "Wave Number Spectra in the Solar Wind, the Foreshock, and the Magnetosheath." In Astrophysics and Space Science Proceedings, 363–68. Dordrecht: Springer Netherlands, 2009. http://dx.doi.org/10.1007/978-90-481-3499-1_24.

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Teixeira, Rui, Maria Nogal, and Alan O’Connor. "On the Calculation of Offshore Wind Turbine Load Spectra for Fatigue Design." In Structural Integrity, 383–90. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-13980-3_49.

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Conference papers on the topic "Wind spectra"

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Wahl, Neil, Daniel Samborsky, John Mandell, and Douglas Cairns. "Effects of Modeling Assumptions on the Accuracy of Spectrum Fatigue Lifetime Predictions for a Fiberglass Laminate." In ASME 2002 Wind Energy Symposium. ASMEDC, 2002. http://dx.doi.org/10.1115/wind2002-23.

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This paper presents an extension of the work described in Reference 1, which dealt only with tensile fatigue loads spectra. Experimental results and modeling have now been extended to simple spectra which cover a full range of loads including compression and reversed tension-compression, as well as WISPERX and other spectra representative of wind turbines, containing a full range of R-values. Experimental fatigue data (over 1100 tests) have been generated for a fiberglass laminate which is typical of wind turbine blade construction, tested under a variety of loads spectra. Constant amplitude data typical of the DOE/MSU fatigue database are then used with various modeling schemes to predict the lifetime under spectrum loading. Several areas of current concern in blade lifetime prediction are explored. First, it is demonstrated that the Miner’s Rule cumulative damage law results in significantly non-conservative lifetime predictions for most loads spectra. Linear and nonlinear residual strength models are easily applied and are more accurate in predicting lifetime; they also provide a prediction of remaining strength as a function of the history of loading prior to failure. Prediction accuracy is also sensitive to the model (exponential or power law) used to represent and extrapolate the constant amplitude S-N fatigue data. A power law representation appears to provide more accurate predictions of lifetime under spectral loading for longer lifetime cases.
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Koval, Andriy, and Adam Szabo. "Magnetic field turbulence spectra observed by the wind spacecraft." In SOLAR WIND 13: Proceedings of the Thirteenth International Solar Wind Conference. AIP, 2013. http://dx.doi.org/10.1063/1.4811025.

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van Zutphen, Hermione J., Philip Jonathan, and Kevin C. Ewans. "A Generic Method to Model Frequency-Direction Wave Spectra for FPSO Motions." In ASME 2008 27th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/omae2008-57481.

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We report a new approach to model the frequency-direction spectrum, in which the frequency-direction spectra from measurements or hindcast studies are fitted simultaneously in two dimensions, frequency and direction. Depending on the amount of wind forcing on the partition, either a unimodal (swell) or bimodal (wind-sea) wave spreading function is adopted together with the spectral form which best fits the frequency spectrum. This paper describes the new method and presents the results on a measured dataset.
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Shaikh, Dastgeer, G. P. Zank, M. Maksimovic, K. Issautier, N. Meyer-Vernet, M. Moncuquet, and F. Pantellini. "3D Hall MHD Modeling of Solar Wind Plasma Spectra." In TWELFTH INTERNATIONAL SOLAR WIND CONFERENCE. AIP, 2010. http://dx.doi.org/10.1063/1.3395828.

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Feynman, J., A. A. Ruzmaikin, and E. J. Smith. "Radial evolution of the high/low frequency breakpoint in magnetic field spectra." In Proceedings of the eigth international solar wind conference: Solar wind eight. AIP, 1996. http://dx.doi.org/10.1063/1.51409.

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Berger, L., C. Drews, A. Taut, and R. F. Wimmer-Schweingruber. "Heavy pickup ion w-spectra at 1 AU with SOHO/CELIAS/CTOF." In SOLAR WIND 13: Proceedings of the Thirteenth International Solar Wind Conference. AIP, 2013. http://dx.doi.org/10.1063/1.4811066.

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Andreev, V. E., A. I. Efimov, L. N. Samoznaev, and M. K. Bird. "Faraday rotation fluctuation spectra observed during solar occultation of the Helios spacecraft." In Proceedings of the eigth international solar wind conference: Solar wind eight. AIP, 1996. http://dx.doi.org/10.1063/1.51356.

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Bieber, J. W. "Cosmic Ray Spectra and the Solar Magnetic Polarity: Preliminary Results from 1994–2002." In SOLAR WIND TEN: Proceedings of the Tenth International Solar Wind Conference. AIP, 2003. http://dx.doi.org/10.1063/1.1618673.

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Efimov, A. I., L. A. Lukanina, L. N. Samoznaev, V. K. Rudash, I. V. Chashei, M. K. Bird, M. Pätzold, et al. "Coronal Radio Sounding Experiments with Mars Express: Scintillation Spectra during Low Solar Activity." In TWELFTH INTERNATIONAL SOLAR WIND CONFERENCE. AIP, 2010. http://dx.doi.org/10.1063/1.3395973.

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Izmodenov, Vlad. "HST Lyman-alpha absorption spectra toward nearby stars as a remote diagnostic of the heliosheath plasma properties." In SOLAR WIND TEN: Proceedings of the Tenth International Solar Wind Conference. AIP, 2003. http://dx.doi.org/10.1063/1.1618542.

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Reports on the topic "Wind spectra"

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Long, Charles E. 1996 Index of Wind Wave Directional Spectra Measured at Harvest Platform. Fort Belvoir, VA: Defense Technical Information Center, August 1997. http://dx.doi.org/10.21236/ada330158.

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Long, Charles E. Annual Index of Wind Wave Directional Spectra Measured at Harvest Platform 1994. Fort Belvoir, VA: Defense Technical Information Center, June 1996. http://dx.doi.org/10.21236/ada311178.

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Elgar, Steve. Improved Paramerizations of Triad and Quartet Interactions in Spectral Wind-Wave Models. Fort Belvoir, VA: Defense Technical Information Center, November 2001. http://dx.doi.org/10.21236/ada390543.

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Billingsley, J. B., and John F. Larrabee. Measured Spectral Extent of L- and X-Band Radar Reflections from Wind- Blown Trees. Fort Belvoir, VA: Defense Technical Information Center, February 1987. http://dx.doi.org/10.21236/ada179942.

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White, D. New Method for Dual-Axis Fatigue Testing of Large Wind Turbine Blades Using Resonance Excitation and Spectral Loading. Office of Scientific and Technical Information (OSTI), April 2004. http://dx.doi.org/10.2172/15007390.

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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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HEFNER, Robert. IHSAN ETHICS AND POLITICAL REVITALIZATION Appreciating Muqtedar Khan’s Islam and Good Governance. IIIT, October 2020. http://dx.doi.org/10.47816/01.001.20.

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Ours is an age of pervasive political turbulence, and the scale of the challenge requires new thinking on politics as well as public ethics for our world. In Western countries, the specter of Islamophobia, alt-right populism, along with racialized violence has shaken public confidence in long-secure assumptions rooted in democracy, diversity, and citizenship. The tragic denouement of so many of the Arab uprisings together with the ascendance of apocalyptic extremists like Daesh and Boko Haram have caused an even greater sense of alarm in large parts of the Muslim-majority world. It is against this backdrop that M.A. Muqtedar Khan has written a book of breathtaking range and ethical beauty. The author explores the history and sociology of the Muslim world, both classic and contemporary. He does so, however, not merely to chronicle the phases of its development, but to explore just why the message of compassion, mercy, and ethical beauty so prominent in the Quran and Sunna of the Prophet came over time to be displaced by a narrow legalism that emphasized jurisprudence, punishment, and social control. In the modern era, Western Orientalists and Islamists alike have pushed the juridification and interpretive reification of Islamic ethical traditions even further. Each group has asserted that the essence of Islam lies in jurisprudence (fiqh), and both have tended to imagine this legal heritage on the model of Western positive law, according to which law is authorized, codified, and enforced by a leviathan state. “Reification of Shariah and equating of Islam and Shariah has a rather emaciating effect on Islam,” Khan rightly argues. It leads its proponents to overlook “the depth and heights of Islamic faith, mysticism, philosophy or even emotions such as divine love (Muhabba)” (13). As the sociologist of Islamic law, Sami Zubaida, has similarly observed, in all these developments one sees evidence, not of a traditionalist reassertion of Muslim values, but a “triumph of Western models” of religion and state (Zubaida 2003:135). To counteract these impoverishing trends, Khan presents a far-reaching analysis that “seeks to move away from the now failed vision of Islamic states without demanding radical secularization” (2). He does so by positioning himself squarely within the ethical and mystical legacy of the Qur’an and traditions of the Prophet. As the book’s title makes clear, the key to this effort of religious recovery is “the cosmology of Ihsan and the worldview of Al-Tasawwuf, the science of Islamic mysticism” (1-2). For Islamist activists whose models of Islam have more to do with contemporary identity politics than a deep reading of Islamic traditions, Khan’s foregrounding of Ihsan may seem unfamiliar or baffling. But one of the many achievements of this book is the skill with which it plumbs the depth of scripture, classical commentaries, and tasawwuf practices to recover and confirm the ethic that lies at their heart. “The Quran promises that God is with those who do beautiful things,” the author reminds us (Khan 2019:1). The concept of Ihsan appears 191 times in 175 verses in the Quran (110). The concept is given its richest elaboration, Khan explains, in the famous hadith of the Angel Gabriel. This tradition recounts that when Gabriel appeared before the Prophet he asked, “What is Ihsan?” Both Gabriel’s question and the Prophet’s response make clear that Ihsan is an ideal at the center of the Qur’an and Sunna of the Prophet, and that it enjoins “perfection, goodness, to better, to do beautiful things and to do righteous deeds” (3). It is this cosmological ethic that Khan argues must be restored and implemented “to develop a political philosophy … that emphasizes love over law” (2). In its expansive exploration of Islamic ethics and civilization, Khan’s Islam and Good Governance will remind some readers of the late Shahab Ahmed’s remarkable book, What is Islam? The Importance of Being Islamic (Ahmed 2016). Both are works of impressive range and spiritual depth. But whereas Ahmed stood in the humanities wing of Islamic studies, Khan is an intellectual polymath who moves easily across the Islamic sciences, social theory, and comparative politics. He brings the full weight of his effort to conclusion with policy recommendations for how “to combine Sufism with political theory” (6), and to do so in a way that recommends specific “Islamic principles that encourage good governance, and politics in pursuit of goodness” (8).
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Wind Turbine Design Innovations Drive Industry Transformation; The Spectrum of Clean Energy Innovation (Fact Sheet). Office of Scientific and Technical Information (OSTI), June 2010. http://dx.doi.org/10.2172/983708.

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