CTIVE flow control by fluidic oscillators has drawn attention in recent years due to their simple and robust design and their effectiveness over a wide range of flow conditions. Figure 1 shows the internal geometry of a fluidic oscillator which consists of a power nozzle, a mixing chamber, two feedback channels and an outlet nozzle. The Coanda phenomenon occurs inside the mixing chamber and causes the incoming flow through the power nozzle to alternately attach to either side of the chamber wall. A portion of the jet enters the feedback channel near the actuator exit and the chamber wall to which the jet is attached. The flow direction in the feedback channel is opposite to the direction of the jet flow. The reversed flow exiting the feedback channel interacts with the main jet near the chamber entrance and pushes the jet to the opposite side of the chamber wall. This process repeats in the other channel and consequently produces an oscillatory jet at the outlet of the actuator which is shown to be more effective than the steady jets for active flow control applications. The frequency of the jet oscillation is a function of the supply rate, the internal shape and dimension of the actuator.