Vortex induced vibration (VIV) is a phenomenon observed for bluff bodies in a free stream. The shedding of asymmetric vortices from the bluff body results in oscillating hydrodynamic forces acting on the body and thus leading to its vibration. The vibrations cause severe fatigue damage to structures and thereby reduce the operation life of the structures. The study of VIV of long flexible cylindrical structures and the development of VIV suppression methods is therefore an area of active research interest.
During operation at large angles of attack, foils shed vortices from their leading and trailing edges in a similar fashion to the Van Karman vortex street in the wake of a circular cylinder. Because vortices represent a strong low pressure region, the presence of a shed vortex near the foil surface exerts forces on the body that can be harnessed to enhance foil performance.
This study is also done for various offshore platforms.
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