The present paper deals with suppression of vortex induced vibrations (VIV) by introducing radial water jets from circular openings in the wall of the oscillating cylinder. Overpressure within the water-filled cylinder propels water jets blowing out into the ambient flow as a means to alter the vortex shedding process. This flow will introduce a disturbance that is expected to yield reduced VIV amplitudes. Results are presented from experiments in a towing tank testing a spring-supported cylinder with two straight rows of radial water jets along the the cylinder, located at positions +120° and−120° on the cylinder circumference. A smooth cylinder with no openings is tested for comparison.
Direct Numerical Simulations (DNS) have been performed using the Spectral/hp element code Nεκταr. Outflow through openings in the cylinder wall is modeled, and a parameter study is performed where number of jets as well as jet location on the cylinder circumference and jet flow rate are varied.