## 1 Introduction  
In recent decades, interest in renewable energy sources has significantly increased due to the global need for reducing carbon emissions and promoting sustainable development. Wind energy, as one of the most promising areas in this field, has attracted the attention of researchers and engineers. In particular, vertical-axis wind turbines (VAWTs) are gaining considerable interest due to their ability to operate with wind from various directions and their potential for use in diverse geographical conditions. However, VAWTs are associated with several technical challenges, among which the issue of self-starting is of particular importance. This paper investigates the aerodynamic characteristics and self-starting capabilities of Darrieus-type rotors with asymmetrical blades. The focus is on developing new blade designs to improve starting performance and increase the overall efficiency of wind energy converters (WECs). This paper focuses on investigating alternative blade designs, to provide a lightweight self-starting rotor, as well as improving their performance. Among the recently investigated concepts, a combined design incorporating elements of Savonius and Darrieus rotors deserves special attention. This hybrid offers a self-starting solution for the Darrieus rotors at different wind speeds and shows improved power performance compared to traditional Savonius rotors. This line of research promises significant promise for improving the efficiency and reliability of wind-driven power plants [1; 2; 3; 4; 5]. [PERSON] et al. have developed a new blade configuration for the Darrieus-type vertical-axis wind-driven plants that provide start-up at low wind speeds. This development aims to improve the performance and efficiency of vertical axis of rotation of wind-driven plants by solving one of the main problems faced by these plants [6]. [PERSON] et al. investigated the aerodynamic performance of wind turbine blades using CFD environment; in particular, they analyzed different blade configurations to optimize their efficiency under different wind conditions [7]. Various researchers have presented a variety of approaches to solve the problem of poor self-starting of the Darrieus turbine. A study on the combination of Savonius and Darrieus technologies for complete self-starting and improved efficiency over simple Savonius is presented in paper [2], the use of guide vanes is studied by the authors of paper [8], the use of mechanical blade angle optimization systems is investigated in paper [9], and specialized blades that change their shape during rotation resembling an aerodynamic profile is presented in papers [10,11]. All these innovations face certain difficulties: some models are too complex to manufacture and require stable support, others are limited in operating range and maximum efficiency despite the increase in starting torque. Nevertheless, the use of asymmetric or curved blades in the shape of the airfoil represents a promising design prospect that provides excellent launch characteristics [12]. However, such designs are too complex to manufacture and install in urban settings where space is limited. Earlier attempts have been made to improve the self-starting performance of wind-driven plants, mainly focusing on the optimization of static geometric parameters such as turbine density, blade curvature and thickness, blade offset angle and blade forward angle, etc. [13]. Other approaches proposed to improve self-starting include the use of tilted blades [14,15], flexible snails [16], variable pitch [17], etc. [PERSON] et al. conducted a numerical and experimental investigation into the performance of a vertical-axis wind turbine (VAWT) rotor equipped with auxiliary blades [18]. Although these approaches contribute to improving a starting torque, the problems reported are mainly a reduction in maximum efficiency and operating range. Nevertheless, the use of an asymmetric bending profile [19] may be a promising design aspect to achieve good launch performance.