A energia eólica é, atualmente, uma das fontes de eletricidade que mais crescem em todo o mundo. Porém, especialmente no Brasil, ainda é muito difícil a localização de regiões com ventos confiáveis para a implantação de um parque eólico pois não existe uma densidade de dados válidos que sirvam de garantia de eficiência do parque. Assim, o desenvolvimento de modelos que simulam as condições de vento são extremamente importantes para estudos e pesquisas na área. Neste sentido, dados de reanálises

The main objective of this study is to analyze the influence of a wind farm on the variables that control the flow in the atmospheric boundary layer. The simulated period was the whole year of 2008, using a control simulation performed with the Weather Research and Forecasting model (WRF), and the wind farm model (the WRF model with the module Fitch, which parameters the influence of wind turbines on atmospheric flow). Both simulations using the Yonsei-University (YSU) boundary layer parameterization. From the control simulation is made the validation of the model, using observational data collected in two automatic stations of the National Institute of Meteorology (INMET) in the cities of Alegrete-RS and Quaraí-RS. The wind farm idealized in this work has 100 wind generators of 3 MW of power with 120 m in height and with rotor measuring 125 m in diameter. Although the wind speed responds adequately, the temperature and turbulence of near-surface runoff decrease. Analysis of the dependence of near-surface turbulence with vertical stability indicates that the turbulence being generated by the turbines is not reaching the surface. This problem may be related to the chosen boundary layer parameterization.

Identification and estimation of the period of non turbulent oscillatory processes in the stable boundary layer through autocorrelation functions

Resumo A transição de regime de escoamento laminar-turbulenta é importante na maioria das áreas de aplicação de mecânica de fluidos. Na camada limite planetária (CLP), o escoamento é predominantemente turbulento. Todavia, logo após o ocaso, a incidência de radiação solar cessa e a superfície passa a perder calor através da emissão de ondas longas, dando origem a uma camada limite estavelmente estratificada (CLE), onde a turbulência pode ser suprimida praticamente em todas as suas escalas. Nestas condições

The proper description of the atmospheric flow in the stable atmospheric boundary layer is one of the most complex tasks to be performed by numerical models of weather and climate prediction. Most of the parameterizations used in these models are based on the statistical theory of turbulence in their conception. However, this theory is valid only for a flow in which turbulence is homogeneous, isotropic and stationary, a conditions that are not commonly found overnight. Basically, the nighttime flow can be classified in two major regimes: very stable, where turbulence is almost entirely suppressed; and weakly stable regime, with intense turbulent mixing. The transition between these regimes is known as atmospheric coupling, and it can happens a lot of times along the same night. In this work, we implemented a single column model with turbulence closure 1.5, in three different configurations and three different turbulence formulations. In general, the model results show that, all the configurations are able to reproduce the average characteristics of the flow in the weakly stable conditions.