Some results on electromagnetic control of flow around bodies

The flow around bodies (cylinder, plate) can be controlled by applying electromagnetic forces originating from electrodes and permanent magnets suitably placed on the surface of the body. There is a large variety for applying those forces with respect to the geometrical arrangement and the electrical current feeding the electrodes. The goals of this approach are flow stabilization, drag reduction or manoeuvrability of the body in an electrically low-conducting fluid like seawater. We present experimental and numerical results for a low Reynolds-number range of 200 < Re < 4000. Experiments were performed using a copper sulphate electrolytic solution and a sodium hydroxide loop. Flows are considered around a cylinder and over a plate, with
Lorentz forces being parallel to the body surface. Experimental results will be presented for the body drag and the wake flow structures depending on different
regimes of electromagnetic forcing. In particular, we distinguish between the
regimes of direct, frequency-variable sinusoidal or pulsed electric currents. Numerical results confirm the physical tendencies at least for lower Reynolds numbers. Parameter ranges will be given for an optimal electromagnetic flow control in terms of drag reduction and flow laminarization. The energetic balance will be discussed.