MECHANISM OF INTERFERENCE GALLOPING OF 2 IDENTICAL CIRCULAR-CYLINDERS IN CROSS-FLOW

Cylinders placed close together may be excited by a self-sustained oscillation, the so-called ''interference galloping''. This phenomenon occurs at critical wind directions beta(crit), when the wind speed exceeds a critical wind speed (onset velocity u(0)). Large vibration amplitudes may be established and structural safety may be affected. This paper presents results of current experimental investigations of two identical cylinders placed in cross flow with small spacing ratios and low Scruton numbers. Ideas for a theoretical solution of the problem will be explained and discussed.