Vortex Induced Vibration (VIV) phenomena cause uncontrollable motions of offshore platforms, as well as fatigue damage and failure of components such as cables and risers. The effects of VIV need to be addressed early in the design process to avoid costly platform damage and costly retrofits, such as hydrodynamic strakes for platform tendons.

In order to compete in the International Student Offshore Design Competition, our platform design addresses five fundamental area of technical competency (General Arrangement and Overall Hull/System Design, Weight, Buoyancy and Stability, Global Loading, General Strength and Structural Design, Risk Assessment) and three specialized areas of technical competency unique to a VIV optimized design (Hydrodynamics of Motions and Loading, Fatigue Strength, and Structural Analysis: global and local strength) Our design optimization process begins with a four-caisson, four-pontoon tension leg platform, operating at a depth of 3,000 ft. Hydrostatic and hydrodynamic analysis for design iterations are performed by our own MATLAB script, which calculates the effects of motions due to vortex induced vibration. Some structural analysis is done with a commercial Finite Element Method software program. Structural analysis will also address fatigue loading from VIV and hydrodynamic tendon design options for VIV such as tendon strakes, foils, and alternative geometry. Our design includes risk-based analysis and conforms to class society rules and regulations. Our design also draws on research experience with VIV of multiple, flexible cables in a Reynolds-scaled controlled environment.