The funnel effect and its practical benefits in wind applications

Although wind technology has been greatly improved during recent times, the available technical know-how is not yet adequate to develop reliable wind energy systems functioning at low wind speeds. The developments of wind energy converting systems working at low wind speeds of 3-5 m/s, which are available for a considerable period of the year in the major part of the continental locations, remain unfulfilled. This issue continues to be a matter of great concern for wind research. This paper analyzes some profiles derived from hill effect and tunnel effect - a funnel concept of amplifying the wind speed before it comes in contact with the rotor blades. Furthermore we analyze the amount of practical benefits derived from using a funnel to increase wind speed.