Wind energy
Installations that use wind energy are classified by the position of the rotation axis as the ones of horizontal axis and vertical axis. The most widely spread are horizontally axial installations. This happened due to the rapid development of military aviation and shipbuilding in the beginning of 20-s of XX century. To finance the development of a theoretical base of aircraft and ship propellers, huge funds were allocated in the leading countries of the world such as USA, UK, Germany, Japan and the USSR. This funding has continued for nearly 80 years up to present times. The type of a modern wind turbine has been dictated by these circumstances, since impellers have been a byproduct of theoretical and practical development of propellers. Nowadays, anyone who is interested in windmills will say that the efficiency of horizontal axis impeller (blade wind turbine) is within 0.6 – 0.7, and «clumsy» vertical axis one- up to 0.39. However, the research of the author of this article refutes these parameters. Actually, the theoretical efficiency factor of a blade wind turbine, according to one of the founders of Fluid Dynamics E. Zhukovsky, is 0.593. The real efficiency of a modern wind turbine, according to independent experts, is 0.42 – 0.43, which is very close to the value of 0.39 of a vertical axis wind turbine. But, according to the author of this article, the unenviable fate of vertical axis rotors has been determined by their impracticality, especially in aviation. To determine the correct shape of propellers and to test them in laboratory conditions, wind tunnels have been created. Theoretical errors in the simulation in...
