Vortex Induced Vibration
Vortex Induced Vibration (VIV) is an important source of fatigue damage of riser systems and subsea equipment. The flow around a riser can create vortices which are shed downstream and this can cause in line or more damaging cross flow vibrations to be induced for certain conditions.
Investigating the Presence of VIV
VIV is generally assessed as part of the global riser analysis, however, it can be investigated as a separate study. Shear7 is the main tool for investigating the presence of VIV and consequential fatigue damage.
A linearised modification of the OrcaFlex or Flexcom global riser model can be used in combination with Shear7 to determine the fatigue life of individual components in the riser system. In addition to this, OrcaFlex also has a wake oscillator module and this can use the full non-linear OrcaFlex global riser model to investigate VIV.