Control of self-oscillating systems

In order to obtain a mathematical model of a self-sustained oscillation, a Van der Pol oscillator can be enhanced upstream and downstream with transfer functions identified from measurements. Using a specific engineering control technique, the above model has been used to define a control law aimed at suppressing the oscillation. The method has been applied to a two-dimensional buffet observed on an airfoil in a wind tunnel. The results obtained by applying this law confirmed the authors theory, thus, validating the principles of this type of modelling and design. The same method was successfully applied to the Greitzer model of a compressor surge.