The EXWAVE JIP: Improved Procedures to Calculate Slowly Varying Wave Drift Forces on Floating Units in Extreme Seas

The EXWAVE Joint Industry Project (JIP) was initiated with the aim of improving methods and standard industry practice in design prediction of nonlinear wave loadings on Mobile Offshore Drilling Units (MODUs) induced by severe and steep seastates. The focus is on slowly varying wave excitation, including wave-current interaction effects. The present paper describes the technical background which led to the EXWAVE JIP, the project objectives, the planned work program and initial results. An important part of the work program consists on performing model tests with representative floating structures. Two floating structures have been selected for investigation, namely a semi-submersible drilling rig and a floating production storage and offloading vessel (FPSO). Comparisons between experimental results and standard numerical calculations are presented for the semi-submersible. Computational fluid dynamics (CFD) is applied for detailed analysis and interpretation of complex physical phenomena.