The current research work illustrates the optimization of vertical axis Wind Turbine (VAWT) blades with implementation of added winglets displaying improved self-starting capabilities. The application of improved design is to be utilized in a university campus located in the United Arab Emirates (UAE) in order to reduce its margin of consumed electrical energy by 15%. This work is conducted over a mean wind speed value of 5 m/s achieved in a one-year period at a specific altitude of 50 m in the UAE. Two aerodynamic simulation softwares are adopted, namely ANSYS FLUENT CFD and QBlade, with designs being modelled using AutoCAD. The analytical analysis includes some aerodynamic characteristics such as power, lift, and drag coefficients. Through 2D-computational fluid dynamics (CFD), the simulation study tests 20 different symmetrical as well as asymmetrical airfoils including the cambered S-0146 with 26. 83% higher power output and lower noise amongst the test subjects. Turbine torque for the added winglet design results in 4. 1% higher compared to the benchmark. The modified design aims to produce at least 2% more power, and has an improvement in self-starting of at least 20%. VAWTs tend to have a higher potential and sensitivity towards wind direction (no yawing mechanism required), illustrating them as more cost-effective. The future scope includes utilizing the wind lens technology to increase the free-stream velocity.

Wake generated by wind turbine can greatly influence the performance of downstream turbine. To better understand the wake self-similarity characteristics of vertical axis wind turbine (VAWT), the shear stress transport (SST) turbulence model with the addition of the γ-Reθ transition model is performed to model a two-blade VAWT at different operating conditions. The simulated blade surface pressure and torque are compared with existing experimental results for validation. Results show that, the simulated results after considering the transition model are more consistent with the experimental results. Analysis of the flow field shows that the average streamwise velocity of the wake in the horizontal plane under different tip speed ratios is asymmetry, but symmetric in the vertical plane. Further analysis indicates that, at different downstream positions, the non-dimensional streamwise velocity deficit in the vertical plane remains self-similarity and basically coincides with the Gaussian distribution curve exclude the wake edges. In addition, the larger the tip speed ratio, the easier streamwise velocity deficit reach self-similarity state at downstream of the VAWT. The results of this study will be helpful to establish the wake model of the VAWT.

In the present situation and considering the dangers that affect human life and the environment, it is necessary to expand the use of renewable energy that is available in all geographical areas. Environmental pollution caused by urban life has attracted researchers attention to the use of renewable energy such as vertical axis wind turbines (VAWTs) with the aim of urban application. Because of their unique features, these turbines can provide the electricity needed for the targets, but to date, less attention has been paid to their tower structure. A wind turbine tower is one of the main and costliest components of wind systems. In this paper, based on the standards of turbine design and its structure, an algorithm was presented to create more resistance and strength in the tower structure and control the tower's deflection caused by incoming loads. Different models of simple monopole tower, variable cross-section monopole tower, monopole tower with channel beam control, and monopole tower with lateral restraint in the case study of Iran were simulated. Results show that models with lateral restraint have the lowest deflection of about 3 to 5 cm and, in addition to passing all design standards, the members' stress ratio is allowed within the limit.