Modeling the Wind Turbine Profiles Assuring the Maximum Lift Force With Low-Noise Operation for Variable Wind Velocities

The paper presents a new solution for the wind turbine profile shape modeling based on the concept of the maximum lift force, capable to be produced at different values of the wind velocities. The profile is designed and realized in accordance with the new concept emerged in the last decade, on the operation of the wind turbines with maximum lifting force. The purpose is to provide a low-noise during operation because a negative effect on the medium and long-term operation of the wind turbines (wind farms) is the noise that affects the flight of birds, terrestrial animal life, and especially human communities. Various sources generate independent acoustic emissions on wind profiles, such as the turbulent flow, the interaction of the turbulent boundary layer area of the trailing edge, the flow separation, and the boundary layer separation of vortices formed in the zone of the trailing edge. There is also considered the influence of the apparent wind on the incidence variation of the profile. In order to maintain an optimum angle of attack relative to the wind velocity, a fixed blade inclination must increase its speed to be proportional to the wind. Thus, to maximize the aerodynamic performance, the rotor must spin faster when the wind intensity increases. Measurement of the acoustic signal requires electronic devices that operate on electric signals obtained from the conversion of the pressure variations in voltage or variations in electrical current. The noise caused by the turbulent flow is generated primarily by the sharply pointed leading edge and cannot be diminished. There are presented some numerical results correlated with the measurements made in the field.