Investigation of Low-Frequency Pitch Motion Characteristics for KRISO Standard Offshore Structure (K-Semi) Moored with a Truncation Mooring System

Investigation of Low-Frequency Pitch Motion Characteristics for KRISO Standard Offshore Structure (K-Semi) Moored with a Truncation Mooring System

Blog Article

In this study, a model test was carried out to evaluate the station-keeping performance of Korea Research Institute of the Ships and Ocean Engineering (KRISO) standard semi-submersible, K-Semi in the Deep Ocean Engineering Basin (DOEB).The test was performed using a 1/50 scaled model with 12 mooring lines.The water depth was set to 3.2 m using a moveable bottom structure and truncated mooring lines.

The dynamic behavior of the K-Semi was examined using a free decay ultra max dog shampoo test and regular wave as well as irregular wave tests of 1800.Large surge, heave and pitch due to drift motion from second-order effect were observed.The reason for the excessive low-frequency pitch motion is attributed to the restoring force and moment related to the mooring system as excessive surge occurred.The numerical model of K-Semi with the truncated mooring system was tuned and calibrated using model test results such as free decay and regular wave tests.

Through numerical analysis, the motion characteristics of the K-Semi were compared with irregular model test results.In the case of a semi-submersible using a mooring system, it 8n joico lumishine is observed that excessive pitch motion due to vertical restoring force and moment may occur when large horizontal displacement occurs.The effect of low-frequency pitch motion related to surge motion is an important factor in upwell estimation as well as second-order motion in referred DNV-GL OTG13.