Background

Recent experience in model tests has shown that moored LNG carriers with their inherent low damping characteristics can be very sensitive to small amounts of low frequency wave energy. The "Shallow Water Hydrodynamics" seminar held in Wageningen February 2005 confirmed that there is a lot of attention for this subject and that work on this subject is currently performed by various independent parties. The sHAllow Water Initiative JIP intends to combine the expertise and efforts of both coastal engineers and hydrodynamic engineers and to focus their work on improving the motion and mooring prediction methods, especially for shallow water.

Objectives

To improve the reliability of offshore (LNG) terminals in shallow water by using the combined expertise of offshore hydrodynamics and coastal engineering to better address key issues regarding motion and mooring prediction methods in shallow water.

Benefits and Deliverables

• A state-of-the-art overview of nearshore wave modelling.
• A wave-splitting tool for model basin tests and guidelines to correctly use this tool, allowing an uniform analysis of model basin tests, independent of basin, contractor or oil company.
• A database of current coefficients for LNG carriers, more appropriate than the currently often used OCIMF database for VLCCs.
• A summary report (20 to 30 pages max.) with detailed guidelines on hydrodynamic aspects on LNG terminal design, summarising all reports and covering the whole scope of work of the HAWAI JIP.
• Software:
  a. a special executable version of HYDROSTAR (‘HYDROSTAR-Current’) covering the wave-current interaction in shallow water.
  b. a special executable/binary program module for the evaluation of the QTF in multi-directional waves that can be coupled to other diffraction codes.
  c. a special executable/binary program module for new formulations of second-order wave loads that can be coupled to other diffraction codes.