Studying the drag of a two-bladed wind turbine in the operating mode

In this paper, we consider aerodynamic characteristics of two rotating cylinders transversely streamlined by an air flow. The paper presents the results of experimental studies on determining the force of drag and drag coefficient of a two-bladed wind turbine based on the Magnus effect with smooth rotating cylinders in the range of air flow velocities from $4$ to $13$ m/s ($\mathrm{Re} = 26800$–$105000$) at a constant number of the cylinder rotation around its own axis. From the experimental data, the optimum value for the development of wind turbines operating based on the Magnus effect is determined. The results showed that an increase in the Reynolds number leads to a decrease in the drag coefficient since the drag coefficient is proportional to the force of drag but inversely proportional to the square of the speed value. It is shown that the coefficient of drag and the coefficient of lift depend on the Reynolds number and the number of revolutions of the cylinder. Conditions under which the Magnus effect helps to maximize the lifting force and, consequently, to increase the efficiency of the wind turbine are experimentally determined.