# Optimizing Bladeless Wind Turbines: Morphological Analysis and Lock-In Range Variations
## 6 Conclusions  
Based on the experiment results, it can be concluded that the geometry's shape, particularly its impact on the diameter, significantly affects the Lock-In range. This influence either extends the range towards higher Reynolds number (Re) values or reduces and shifts it towards lower Re values. Predicting the maximum Lock-In range value is feasible using the equation Re (max Lock-In) = 0.30 \(\alpha+4.06\), boasting a high predictive capacity with an R2 of 0.99. Considering that the power extracted by the wind turbine is related to the cube of the velocity, this equation is equally related to the cube with respect to the power, considering that the rest of the parameters are constant, as stated in Equation (6). Moreover, higher diameters correspond to increased maximum RMS values, indicating elevated energy generation. Specifically, a 3.2\({}^{\circ}\) divergence angle displays roughly a 12% surge in maximum RMS value compared to a straight shape at 0\({}^{\circ}\). While surface roughness showed a slight impact, causing a marginal reduction in the Lock-In range, its influence was not pronounced. Nevertheless, this suggests that increased surface roughness might diminish the Lock-In range, potentially affecting the performance of slender circular-shaped wind energy harvesters based on VIV, as evidenced in this study. These results provide insights into the performance expectations for large-scale wind energy harvesters across different scales, underscoring the pivotal role of geometric adjustments in enhancing energy capture efficiency. The demonstrated ability to predict the Lock-In range with high precision paves the way for optimizing bladeless wind turbine designs, potentially leading to more effective and adaptable wind energy solutions. The findings signify a leap towards maximizing the energy generation potential of wind harvesters, crucial for advancing renewable energy technologies and meeting global energy demands sustainably. Through this study, significant strides in blackless wind turbine technology are underscored, emphasizing the pivotal role of geometry and diameter in determining the Lock-In range, a crucial aspect for enhancing energy efficiency. The derived predictive equation for the maximum Lock-In range value, renowned for its precision, empowers precise projections of device performance, heralding a notable advancement in the utilization and evolution of blackless wind energy systems. In addition, it should be considered that BWT technology is still under development and suffers from the limitations of an immature and developing technology. In fact, to date, there is no unequivocal evidence of its potential success or overtaking conventional wind technology in general. It is true that there are niches in the market not adequately covered by traditional wind machines, both vertical axis- (Sabonius, Darrieus) and horizontal axis-ones (three-blade, etc. ), for example, the distributed energy environment, where the user rarely wants to go up to the roof to change parts or lubricate the device. This new technology could overcome this clear barrier for rotating machines. Another area with potential for BWTs is environments that suffer from very low temperature events. It is well known that classical devices are blocked by ice, and resonant wind turbines do not have shafts that can be frozen. In any case, the market and technological development will prove in the future the suitability of a wind machine approach such as the one studied in this work. Building upon these findings and considerations, future investigations may expand to examine more factors influencing vortex-induced vibrations (VIVs) in blackless wind turbines. Investigating variations in turbine geometry, such as hyperbolic diameter profiles or modifications to the leading-edge design, presents a promising avenue.