This project intends to experimentally study active control methods in order to suppress and/or totally kill the wake instability (vortex shedding) behind bluff bodies. The first geometry that will be studied is the circular cylinder where suction and blowing alternatively will be applied on both sides of the cylinder by means of an active feedback control loop system. Importance will be attached to the fluid dynamical response to control and the understanding of the fundamental fluid dynamic differences between the natural and the controlled systems by studying boundary layer changes, turbulence statistics as well as changes of vortical structures inside the wake. An enhanced comprehension of the fluid mechanics around and behind bluff bodies as well as its effect when applying different control methods is essential in order to develop safer, more energy efficient, and adapted design within many areas of practical application. Furthermore, the project is of central importance in order to reach a fundamental knowledge of the effect of active control and its fluid dynamics. The results will shed new light on fluid mechanics for future development of experimental as well as theoretical models.