Transverse Modal Vibrations of Vertical Tensioned Risers. a Simplified Analytical Approach

The paper examines the physics of riser transverse modal vibrations of the type induced by VIV (Vortex Induced Vibrations). It presents a simplified analytical solution for such vibrations of vertical tensioned risers with uniform linear characteristics. The solution leads to simple expressions for the principal factors of concern including the natural frequencies, the positions of the nodes and anti-nodes, the maximum angular movements at the riser lower end, and the positions and values of maximum riser curvature. The expressions increase understanding of VIV of deepwater risers under lock-inconditions.