Two-Frequency Averaging in the Problem of Motion of a Counter-Rotating Vertical Axis Wind Turbine

Counter-Rotating Savonius Wind Turbine

“…Correlation between solutions of the system (5) and the averaged system (6) over a finite time interval is described by the theorem [12] (similar averaging was performed in the model of a double rotor Darrieus wind turbine in [3]).…”

“…In more complicated cases of averaging over angles, the behavior of the system near a resonance may not be described well by the averaged system: trapping into resonance may occur [13,14]. But coupling terms in (5) do not depend on the angles, so the behavior near a resonance is described correctly by the same averaged system (6), at least, over finite time intervals (the corresponding averaging procedure is performed in [3] for the system with similar coupling terms).…”

“…The level of electrical load is adjusted in order to increase the power efficiency of the turbine. For the case of a small-scale Darrieus type counterrotating wind turbine, this effect was demonstrated in the context of the model [3]. In general, the counter-rotation scheme can be applied for a wide range of classical wind turbines [4] and even for novel types of vertical axis wind power systems such as those proposed in [5][6][7].…”

“…The steady operation modes of this device are studied that correspond to asymptotically stable fixed points of the dynamical system. The principal scheme of analysis of the system is rather similar to that applied in [3,8].…”