# Design and Optimization of Vertical Axis Wind Turbines Using QBlade
## 1 Introduction  
Recently, there are many researchers from the academic and industry sectors that have turned their attention to developing the vertical axis wind turbine (VAWT), where the main advantage of the VANTs is capturing the wind from any direction. This is considered a significant feature in urban areas, where it is difficult to know the major direction of wind due to the presence of a high number of obstacles (natural and unnatural) and flow-drecting influences. In the urban areas, a new idea has been introduced to increase the production of clean energy, by installation of the small power vertical axis wind turbines on the roof of high constructions. There is another method that encouraged to build the offshore vertical axis wind turbines with huge sizes. Figure 1 shows different typical vertical axis wind turbines. On the other hand, many other problems appeared during the design and after installation of the vertical axis wind turbines such as unbalance, vibration and difficulty to expect the output power. Extensive experimental research was achieved on the axial wind turbine in the field in addition to developing specialist software that led to introducing a new model by [PERSON]. This model was called the Double-Multiple Stream tube (DMS) model. Two parameters were adopted and used in the circular path that related to the blade and extraction of energy. These parameters were introduced by thefollowing terms in the upstream and downstream rotor halves in relation to the rotational axes [1]. The theoretical approach was applied using QBlade software to investigate and analyze different types of airfoils such as DU-06-W200, NACA 0018, and NACA 0021. The produced power assuming different configurations of the twist angle (\(\psi\) = 30\({}^{\circ}\), 60\({}^{\circ}\), 90\({}^{\circ}\), and 120\({}^{\circ}\)) for 1 kW axial wind turbine was analyzed. The extracted energy by the wind blade when reducing the fluid velocity was also determined. Acceptable results were obtained based on the principle of Double-Multiple Stream tube model (DMS). Additionally, it has been found that reliable results can be obtained for different configurations of the axial wind turbine using blade design simulation tool, where the cost and time will be much higher when using the experimental work to obtain the same results [2]. The main objective in the design of wind turbine is to obtain the optimal solution of the VAWT based on the new design approach to enhance the extracted power by minimizing the changes excluding the movable parts. The influences of the change in the aspect ratios as well as the aerodynamic shape using a classical Darrieus rotor with SANDIA shape was studied. NACA0018 and NACA0012 blade profiles were used to enhance the characteristics of the rotor. It was found that each shape of the aerodynamic and aspect ratio has a significant impact on the output power. These results encouraged more researchers to investigate in this area to enhance the performance and output power of the vertical axis wind turbine [3]. Previous studies aimed to obtain the optimal design of the vertical axis wind turbine using QBlade software. It was found that the main advantage of using this software was analyzing the velocity of wind that comes from different directions with high accuracy, where the installation of generators and connecting the electrical cables for this kind of wind turbine is easier and of less cost compared with the horizontal wind turbine. The wide range of results and the high accuracy led to making QBlade software to be a significant design tool to analyze different kinds of wind turbines [4]. This software was used to study the effect of thickness of the airfoil blade on the behavior and performance of the vertical axis wind turbines. The results can be presented by using different kinds of plots; therefore, it can be found that the optimal design is based on the different aerodynamic governing features.