The flow around a cylinder is controlled by applying a Lorentz force parallel to the cylinder surface. Experimental and numerical results will be given both for a steady and an oscillating electromagnetic forcing.
Static forcing is able to prevent separation of the boundary layer or to provoke it, depending on the force direction. Thereby the Karman vortex street is strongly modified, in case of downstream forcing separation can be suppressed resulting in a serious reduction of form drag. Increase of the electromagnetic forcing even results in thrust production leading to a jet evolving from the cylinder rear.
The time dependent forcing is investigated for two different configurations, symmetric and antisymmetric forcing, respectively. In both cases the forcing frequency has a strong influence on the resulting flow. Results from flow visualizations in a Reynolds number range between 500 and 1500 will be given together with numerical simulations. The relation of the experiments to comparable cases of oscillatory rotating and vibrating cylinders will be discussed.