A5003457053- Wind and Air Flow Studies
- Wind Energy Research and Development
- Meteorological Phenomena and Simulations
- Fluid Dynamics and Turbulent Flows
- Fluid Dynamics and Vibration Analysis
- Aerodynamics and Fluid Dynamics Research
- Energy Load and Power Forecasting
- Aeolian processes and effects
- Probabilistic and Robust Engineering Design
- Advanced Aircraft Design and Technologies
University of Agder
2016-2018
Technical University of Denmark
2012-2015
Danish Energy Association
2014
Abstract A velocity spectral tensor model was evaluated from the single‐point measurements of wind speed. The contains three parameters representing dissipation rate specific turbulent kinetic energy, a turbulence length scale and anisotropy. Sonic anemometer taken over forested an agricultural landscape were used to calculate for neutral, slightly stable unstable atmospheric conditions selected speed interval. above forest nine times that at site. No significant differences observed in...
A spectral-tensor model of non-neutral, atmospheric-boundary-layer turbulence is evaluated using Eulerian statistics from single-point measurements the wind speed and temperature at heights up to 100 m, assuming constant vertical gradients mean temperature. The has been previously described in terms dissipation rate $$\epsilon $$ , length scale energy-containing eddies $$\mathcal {L}$$ a anisotropy parameter $$\varGamma Richardson number Ri, normalized destruction variance $$\eta _\theta...
Abstract The cross-spectral phases between velocity components at two heights are analyzed from observations the Høvsøre test site and field experiments under Cooperative Atmosphere-Surface Exchange Study in 1999. These represent degree to which turbulence sensed one height leads (or lags) time other height. phase angle of cross-wind component is observed be significantly greater than for along-wind component, turn vertical component. increase with stream-wise wavenumber separation distance,...
Abstract A spectral tensor model is presented for turbulent fluctuations of wind velocity components and temperature, assuming uniform vertical gradients in mean temperature speed. The built upon rapid distortion theory (RDT) following studies by Mann Hanazaki Hunt, using the eddy lifetime parameterization to make stationary. buoyant driven via five parameters: viscous dissipation rate ε, length scale energy-containing eddies L, a turbulence anisotropy parameter , gradient Richardson number...
This paper deals with modelling of wake dynamics under influence atmospheric stability conditions different from neutral. In particular, it is investigated how the basic split in turbulent scales, on which Dynamic Wake Meandering model based, can be utilized to include effects this model. done partly by analyzing a large number turbulence spectra obtained sonic measurements, dedicated full-scale LiDAR measurements directly resolved. The theory behind generalizing non-neutral are summarized...
Production as well loading of wake exposed wind turbines is known to depend significantly on stability the Atmospheric Boundary Layer (ABL), which adds a new dimension design farm turbines. Adding this aspect in turbine makes number cycle computations blow up with factor equal representative bin classes. The research question be answered paper is: Can an ABL probability distribution meaningful way collapsed into class based (predefined) confidence level.
The purpose of this study is improve the predictive capability Dynamic Wake Meandering (DWM) model generalized to non-neutral atmospheric boundary layer (ABL) conditions in general and under stable ABL stratification particular. emphasis on rotating wind turbine components, improvement focus intimately linked a newly developed refinement classic Monin-Obukhov theory, which, for stratification, primary results less pronounced mean shear outside surface layer, where most modern turbines are...
The aim of the present paper is to demonstrate capability medium fidelity modelling wind turbine component fatigue loading, when turbines are subjected wake affected non-stationary flow fields under non-neutral atmospheric stability conditions. To accomplish this we combine classical Dynamic Wake Meandering model with a fundamental conjecture stating: Atmospheric boundary layer affects primary meandering dynamics driven by large turbulent scales, whereas expansion in frame reference hardly...
We present a homogeneous spectral tensor model for wind velocity and temperature fluctuations, driven by mean vertical shear gradient. Results from the model, including one-dimensional spectra associated co-spectra, are shown in this paper. The also reproduces two-point statistics, such as coherence phases, via cross-spectra between two points separated space. Model results compared with observations Horizontal Array Turbulence Study (HATS) field program (Horst et al. 2004). is described...
The cross-spectral phases between velocity components at two heights are analyzed from observations the Høvsøre test site under diabatic conditions.These represent degree to which turbulence sensed one height leads (or lags) in time other height.The phase angle of cross-wind component is observed be significantly greater than for along-wind component, turn vertical component.The and increase with stream-wise wavenumber separation distance, but there no significant change velocity.The angles...
In this paper, we analyse the simulated and measured wind data with respect to their spectral characteristics effect on turbine loads. The synthetic is generated from a stochastic full-field turbulent simulator - TurbSim for neutral stability conditions. We first investigate model velocity spectra and, coherence model, by comparing results measurements. second part via two cases; without adding coherent events. Finally, compare loads calculated using FAST simulation of 5 MW reference basis...