Picture taken from: "Vortex Induced Motions of Semi Submersible with Four Square Columns", O. Rijken, S. Leverette and K. Davies, DOT 2004, New Orleans, USA. Picture taken from: "Vortex Induced Motions of Semi Submersible with Four Square Columns", O. Rijken, S. Leverette and K. Davies, DOT 2004, New Orleans, USA.
General information
Vortex Induced Motions (VIM) of a floater are the result of the exciting forces by vortex shedding on the hull of a bluff body, causing response near the resonant period of any of the six degrees of freedom motions. VIM is identical to VIV (Vortex Induced Vibrations), but due to the much longer periods of the motions, the vortex induced vibrations of floating structures are more commonly referred to as Vortex Induced Motions (VIM). VIM can occur on any bluff body exposed to current, such as Spars, semi-submersibles, TLPs and buoys, provided the vortex shedding frequency is close or equal to the natural period of the floating body.

The Trials and Monitoring Department can be involved in full-scale measurements of Vortex Indiced Motions.

Services & Activities
The Offshore Department has a lot of experience in the testing of Vortex Induced Motions of Spars, Semi submersibles and TLPs in the Depressurised Towing Tank. For testing Vortex Induced Motions (VIM), this tank is specially suited due to its long tow length and large cross section (main dimensions: 240 x 18 x 8 m). Uniform current flow is simulated by towing the model in calm water. During these tests the VIM response of the structure is determined and the effectivity of VIM reduction devices (such as helical strakes) is determined and optimised.

Facilities & Tools
VIM model tests are carried out in the following MARIN facilities :

The following tools are used to study Vortex Induced Motions (VIM) :

Software Sales
Some software tools are available for commercial use outside MARIN. A complete overview of these software tools for sale can be found under Software Sales.

Experience
The list below gives a review of VIM projects carried out at MARIN:

  • Perdido Regional Host Spar (Technip/Shell, 2006)
  • Blind Faith semi (Chevron/AkerKvaerner, 2005)
  • Tahiti Spar (Technip/Chevron, 2004)
  • Genesis Spar (Technip/Chevron, 2003)
  • Mad Dog Spar (Technip/BP, 2002)
  • Holstein Spar (Technip/BP, 2002)
  • Murphy Medusa Spar (McDermott/Murphy, 2001)
  • King Spar (BP Amoco, 1999)
The following Joint Industry Project (JIP) will be focussed on Vortex Induced Motions :

  • Joint Industry Project ‘Current Affaires
Most recent papers on Vortex Induced Motions (VIM) presented by MARIN
(complete overview of papers can be found under Publications)

Current Modeling Experience in an Offshore Basin
Bas Buchner and Jaap de Wilde (Maritime Research Institute Netherlands MARIN), OMAE Conference, Estoril, 2008

Exploratory Free Standing Riser VIM Model Tests
Jaap de Wilde (MARIN), 3rd International Workshop on Applied Offshore Hydrodynamics (IWAOH), Coppe/UFRJ - LabOceano, Rio de Janeiro, 2007

Model Tests on the Vortex Induced Motions of the Air Can of a Free Standing Riser System in Current
Jaap de Wilde (MARIN), DOT Conference, Stavanger, 2007

Flow Induced Motions of Multi Column Floaters
Olaf J.Waals (MARIN), Amal C. Phadke (ConocoPhillips) and Stephen Bultema (Bultema Marine), OMAE Conference, San Diego, 2007

The Effect of Mooring System and Sheared Currents on Vortex Induced Motions of Truss Spars
van Dijk, R.R.T, Voogt, A.J. (MARIN), Fourchy, P. (Murphy Oil Corporation) and Mirza, S. (Agip Petroleum, Inc.), OMAE Conference, Cancun, 2003

Most recent articles in MARIN Report on Vortex Induced Motions (VIM)
(complete overview of papers can be found under Publications)

New stereo-PIV system proves a valuable tool for flow measurements Report gives an overview of stereoscopic-PIV
Stereo Particle Image Velocimetry (PIV) is an advanced measuring technique for obtaining 3D velocity information in a plane. PIV can be used to investigate the spatial structure of a flow by efficiently measuring in multiple...

Current Affairs JIP improves current insight
In the last few years the importance of current on the behaviour of offshore structures has become evident. For example, the strong loop current in the Gulf of Mexico delayed installation projects and resulted in Vortex Induced...

Computational Fluid Dynamics now applied to offshore structures
MARIN has applied and developed Computational Fluid Dynamics (CFD) for several decades in the field of ship resistance and propulsion but now the offshore industry is also asking for CFDbased advice. Therefore, the time...

Deep pit attracts full-tendon Shenzi TLP
With its deep pit of 30 metres, the Offshore Basin offers the possibility of testing TLPs with their full-tendon length, even in ultra-deep waters. This allows reliable testing, including important effects such as set-down...

MARIN conducts Thunder Hawk VIM testing
In the last six to seven years, MARIN has extended its model test experience into Vortex Induced Motions (VIM) on Spars and Deep Draft Semi-submersibles. Recently, the ATLANTIA Thunder Hawk Deep Draft Semi was...

Contact
For more information on how MARIN can help your organisation with the issue of Vortex Induced Motions, please contact:

For model test activities and simulations : Offshore Department
For full scale measurements : Trials and Monitoring Department