Análise computacional do vento sobre o topo de edifícios: variações de direção e velocidade

Abstract

The use of wind generators in built environment is hampered by the non-stationary condition of the airflow in these regions. It is difficult to predict the actual wind behavior near buildings, witch affects the installing viability of a wind turbine. This work aims to perform numerical analysis of airflow over buildings, in order to assist in defining the best positioning of a wind turbine intending to optimize the energy generation in this type of installation site. For this, the acceleration and stagnation fields are identified according to the wind direction and free stream velocity. The ANSYS Fluent (R) software is used to solve the characteristic equations in which the k - c turbulence model is used. A variation analysis of wind incidence angle and velocity is performed in order to understand their influence over airflow near the top of the building, assessing the most favorable or harmful conditions for wind energy generation. It can be concluded that the free stream velocity has little influence on wind acceleration and that the incidence angle of 30º offers higher percentages of acceleration comparing to the other simulated angles conditions, and this acceleration occurs between 3 and 5 meters away from the top. It is also observed that the buildings positioned in angle to the wind direction present more favorable scenarios for the utilization of wind energy in their tops.