Figure 1(a) presents the variation of the angle of attack *α* of a turbine blade over the upstream half of its revolution, i.e., 0 deg < *θ* < 180 deg. At all rotational speeds, the blade overcomes the static stall angle, *α*_{ss}, which means, in terms of physics, that the flow separates and forms a small recirculation or flow reversal zone on the suction side of the blade. At tip speed ratios lower than approx. 3.0, the dynamic stall angle, *α*_{ds}, is surpassed, and physically this means that the separated flow does not reattach on the blade leading to a dramatic reduction in lift. As it can be seen as well from this figure is that the lower the tip speed ratio, the earlier dynamic stall occurs, i.e., *α* > *α*_{ds}, and hence the longer the rotor blade undergoes deep dynamic stall during its rotation. Increasing the value of *α*_{ds}, for instance by selecting an airfoil shape that is less prone to flow separation reduces the extent of deep dynamic stall at given tip speed ratios, and this is beneficial to VATs. Note that if *α*_{ds} is smaller than *α*_{max}, then the blade does not undergo deep dynamic stall as it is the case for *λ* > 3.0 [24].