Thesis
Numerical investigation of ROV deployment onboard a small offshore service vessel for offshore wind farm O&M
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2025
- Thesis identifier
- T17233
- Person Identifier (Local)
- 202169663
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- Aimed at significant cost reduction and reducing the overall greenhouse gas (GHG) emission during the operation, the deployment of remotely operated underwater vehicle (ROV) from a small offshore service vessel (OSV) based on single point mooring system (SPMS) method is recently adopted in offshore renewable energy sector. However, the tension spike in wire, also known as snap load, often occurs when the ROV passes through the wave zone in launching and lifting operation of deployment. This study developed a coupled numerical model of ROV deployment onboard a small OSV positioned by a SPMS for subsea inspection of a fixed or floating offshore wind turbine. The numerical model for predicting wire tension during launch and recovery of ROV is developed and validated by wave flume test of a 1:10 scaled model. The numerical simulations reveal that the ROV deployment at vessel stern along with an appropriate reduction of horizontal distance from the hull are reliable safety strategies for reducing wire tension. By adopting the new deployment strategy, the annual operational capacity can be expanded by approximately 6% when the safe operational limit of ROV under a significant wave height of 1.25 m. Based on the comprehensive numerical simulation, the newly developed safe operating envelope provides a practical recommendation for onboard ROV operation in the operations and maintenance (O&M) of offshore wind farms. As a typical practical offshore operation involving multiple floating body dynamics, the dynamic response characteristics of umbilical cable of ROV, connecting lines of SPMS, and mooring lines of floating offshore wind turbines (FOWT) are investigated under the environmental conditions of the northern North Sea. The coupled numerical model was first validated against the maximum and average tension measurements of connecting lines obtained from full-scale OSV operations at sea for subsea inspection of two different fixed wind turbines. Numerical simulations of coupled OSV-FOWT system indicated that the dynamic tension in umbilical cable and mooring lines, primarily determining the environmental limits of ROV deployment and safe operation, is influenced by wind-wave misalignment and the relative distance between OSV and FOWT. The relationships and safe operational ranges of umbilical cable, connecting lines, and mooring lines were examined in detail to provide further guidance for onboard ROV operations in offshore wind farm maintenance.
- Advisor / supervisor
- Tao, Longbin
- Resource Type
- DOI
- Date Created
- 2024
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PDF of thesis T17233 | 2025-02-25 | Public | Download |