Global sensitivity analysis of mooring variables for taut-moored floating photovoltaic arrays in the South China Sea continental shelf

초록

Traditional mooring design for nearshore shallow water lacks a sufficient theoretical basis. This deficiency may cause large motions and mooring failure risks for floating photovoltaic (FPV) systems. The aim of the study is to investigate critical mooring variables of a taut-moored FPV system suitable for nearshore shallow water in the South China Sea using a Sobol global sensitivity method. A multi-body coupled numerical model is first validated via a scaled model test. Based on the validated numerical model, the time-domain hydrodynamic simulations are performed for the mooring multivariable cases. A multivariable case includes four critical mooring variables: mooring layout patterns (Parallel, V-shaped, Lambda-shaped, Chi-shaped), seabed uplift angle, mooring pretension, and number of mooring lines. The global sensitivity analysis under typical South China Sea states reveal that the seabed uplift angle is the most critical mooring variable, dominating floater motions and mooring tensions, and present that a strong nonlinear interaction exists between the four critical mooring variables. While the Chi-shaped mooring layout combined with a mooring pretension of 0.2 times the minimum breaking load (MBL) gives the best overall performance. Furthermore, the design range of 40 degrees similar to 55 degrees was determined as the optimal seabed uplift angle by the reasonable interpolation method, which can improve the motion stability and mooring safety margin of shallow water FPV systems under complex sea conditions.

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