A control system is presented for controlling operation of a vertical axis wind turbine (VAWT) for generating energy from an incoming fluid flow. The control system comprises at least one flow affecting arrangement associated with at least one blade of the VAWT and a control unit connected to said flow affecting arrangement, the flow affecting arrangement comprising two flow affecting units located in two opposite sides of the blade respectively at a leading edge thereof, each flow affecting unit being operable for creating a blowing jet at the respective side of the blade thereby inducing an increase in a fluid flow momentum, the control unit being configured and operable for selectively activating the flow affecting units in alternating fashion according to a predetermined time pattern to oscillate the blowing jet at the opposite sides of the blade.