The dynamic stall features of a simplified vertical axis wind turbine (VAWT) configuration are analyzed. Wall-resolved large eddy simulations are performed for a NACA0018 airfoil operating as a single blade VAWT, and the operational parameters are set to tip speed ratio lambda = 3, Reynolds number Re = 50,000 and Mach number M = 0.025. The dynamic stall phenomenon has a detrimental impact on the aerodynamic performance of VAWTs, and the aerodynamic drag resulting from the interaction of the blades with the dynamic stall vortex (DSV) hinders the production of useful energy. Consequently, the development of efficient turbines rely on the effective drag reduction induced by the DSV. Here, the unsteady flow is analyzed by visualization of positive and negative finite time Lyapunov exponent (FTLE) fields, which provide analogs for stable and unstable manifolds of the fluid system. The intersection of the FTLE ridges near the wall reveals a saddle point with potential for flow actuation. A linear stability analysis (LSA) is conducted at this saddle point during the airfoil upstroke motion, revealing the moment at which the flow becomes unstable due to a Kelvin-Helmholtz instability. This study focuses on the application of suction and blowing actuation as an alternative for mitigating the undesirable effects of dynamic stall. By introducing disturbances into the boundary layer at an appropriate frequency found from LSA, we can effectively reduce flow separation on the blade by influencing the accumulation of vorticity generated by the coalescence of Kelvin-Helmholtz instabilities developing along the shear layer originating from the separation region.