الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The main objective of the present study is to make use of the low wind speed that is spread all over the world land, in order to produce a useful and economical wind power. This includes finding a method to increase the natural wind velocity that blows over the wind turbines. Therefore, a study has been carried out in order to select and optimize the best geometric shape of a structure accompanied with the wind turbine that generates the highest wind velocity in front of a wind rotor using design the of experiments technique. The present study is based on optimizing the geometric shape of a flanged diffuser augmented wind turbine structure; in order to extract the highest wind velocity, which will in turn, generate the highest wind power if a wind turbine is installed inside the diffuser at the point of maximum air velocity. The nozzle length, diffuser length, flange height, diffuser angle, nozzle angle are the parameters that can control the performance of the diffuser augmented wind turbine (DAWT) structure and accordingly its efficiency. Several combinations of these five parameters are used and compared. The flow velocity predicted by the simulation is analyzed through two different regression models, with and without interaction terms. Those models developed according to multi-linear regression using LU decomposition to solve a system of algebraic equations. These models are validated by comparing their results with CFD results. A regression model with interaction terms lowered the polynomial degree and suggested valid predictions and stable explanations. The results of the numerical investigations let to the best geometric shape of the flanged diffuser, based on the generation of the highest wind velocity inside the flanged diffuser. The results proved that a flanged diffuser equipped with a nozzle length of 0.25D, nozzle angle of 22˚, diffuser length of 1.45D, diffuser angle of 12˚, flange height of 0.9D are the optimum values where D is the diffuser throat diameter. The best geometric shape of the flanged diffuser generates a wind velocity augmented by a factor 1.71. The present study includes also a three dimensional, 3D, model for the augmented structure with and without inserting the wind blades. A comparison between the 2D and 3D cases is performed. The augmented velocity ratio at the diffuser throat decreased from 1.7 to 1.63 after inserting the blades.