Numerical study on truncated model for deep sea mooring lines

Abstract

Since the water depth and model scale are usually limited in water tanks, truncated mooring lines are widely used in the model test for deep sea moored body. In that case, matching of physical parameters between original depth and truncated models are required. The most basic target is the static offset versus restoring force because the matched offset curve guarantees equivalent mooring stiffness of floating body. However, another parameters such as weight, mean tension anddamping are also issues in truncation modeling. This paper carried out some numerical studies regarding the truncation parameters and presented some discussions about matching offset curve, weight, tension and damping at the same time. Floating body and mooring lines are analyzed by HOBEM (Higher Order Boundary Element Method) based convolution and FEM (Finite Element Method), respectively and the coupled responses are simulated. The derived results may provide some guide toimprove truncation model test.