Search results for "Wind profile power law"
showing 6 items of 6 documents
The impact of in-canopy wind profile formulations on heat flux estimation in an open orchard using the remote sensing-based two-source model
2010
Abstract. For open orchard and vineyard canopies containing significant fractions of exposed soil (>50%), typical of Mediterranean agricultural regions, the energy balance of the vegetation elements is strongly influenced by heat exchange with the bare soil/substrate. For these agricultural systems a "two-source" approach, where radiation and turbulent exchange between the soil and canopy elements are explicitly modelled, appears to be the only suitable methodology for reliably assessing energy fluxes. In strongly clumped canopies, the effective wind speed profile inside and below the canopy layer can strongly influence the partitioning of energy fluxes between the soil and vegetation co…
Pitch controller modeling for wind turbine power regulation using feed forward control strategies
2015
In this work, pitch controlled power regulation of a horizontal axis wind turbine coupled with a fixed speed asynchronous generator is studied using SimulationX®. Wind turbines need to be operated as per specified power output vs wind speed characteristics of it. If the wind speed is between the cut-in wind speed and the rated wind speed, then the wind turbine needs to be operated constant Cp. If wind speed is between the rated speed and the cut-off wind speed, then the wind turbine needs to be operated for constant rated power. To extract rated power above rated wind speed a proper controller strategy is required. This work provides a simulation model for power regulation of a horizontal a…
The effect of wind on jumping distance in ski jumping – fairness assessed
2012
The special wind compensation system recently adopted by Federation Internationale de Ski (FIS; International Ski Federation) to consider the effects of changing wind conditions has caused some controversy. Here, the effect of wind on jumping distance in ski jumping was studied by means of computer simulation and compared with the wind compensation factors used by FIS during the World Cup season 2009/2010. The results showed clearly that the effect of increasing head/tail wind on jumping distance is not linear: +17.4 m/ − 29.1 m, respectively, for a wind speed of 3 m/s. The linear formula used in the trial period of the wind compensation system was found to be appropriate only for a limited…
Wind energy potential assessment in order to produce electrical energy for case study in Divandareh, Iran
2014
This paper evaluates the electricity production at Divandareh, a place located at Kurdistan, Iran through wind energy assessment using wind data of the site recorded in duration of a year at three different heights of 10, 30 and 50 meters. For this purpose, a statistical analysis of the measured wind data is performed. According to the US standards, the site is found to be a class-3 wind power site with power density of 336.18 W/m2 at 50 m height. Moreover, dominant flow direction of wind is checked through wind rose plotting. It has been shown that the site is suitable for wind energy development by installing wind turbines with tall towers. Thereupon, four different commercial wind turbin…
Estimation of annual energy output of a wind turbine using wind speed probability distribution
2016
In this work, annual energy output of a variable speed wind turbine is analyzed using annual Weibull wind speed probability distribution function. The power coefficient variation with tip speed ratio in torque control region as well as pitch angle variation for maximum power output from wind turbine are analyzed for identifying control system parameters. The wind turbine power output and variation of power coefficient with tip speed ratio as well as pitch angle are examined / reported using annual Weibull distribution function. Finally the variation of the estimated annual energy output of the given wind turbine with the mean wind speed is presented.
Effects of the air density value on a wind generator electricity production capability
2016
The paper main issue is the evaluation of the influence of the air density value on the electricity production capability of a wind generator. Two different density air mathematical models, where the density has not a constant value, are here taken into account and compared in terms of reliability, accuracy and computational burden. Evaluations are carried out thanks to a horizontal axis wind generator full model built by the Authors in Matlab/Simulink environment. Simulation results are compared with real data.