TY  - EJOU
AU  - Ju, Shen-Haw 
AU  - Huang, Yi-Chen 

TI  - A Time-Domain Irregular Wave Model with Different Random Numbers for FOWT Support Structures
T2  - Computer Modeling in Engineering \& Sciences

PY  - 2025
VL  - 144
IS  - 2
SN  - 1526-1506

AB  - This study focuses on determining the second-order irregular wave loads in the time domain without using the Inverse Fast Fourier Transform (IFFT). Considering the substantial displacement effects that Floating Offshore Wind Turbine (FOWT) support structures undergo when subjected to wave loads, the time-domain wave method is more suitable, while the frequency-domain method requiring IFFT cannot be used for moving bodies. Nonetheless, the computational challenges posed by the considerable computer time requirements of the time-domain wave method remain a significant obstacle. Thus, the paper incorporates various numerical schemes, including parallel computing and extrapolation of wave forces during specific time steps to improve overall efficiency. Despite the effectiveness of these schemes, the computational difficulties associated with the time-domain wave method persist. This study then proposes an innovative approach utilizing different random numbers in distinct segments, significantly reducing the computation of second-order wave loads. This random number interpolation ensures a smooth curve transition between two segments, emphasizing minimizing errors near the end of the first segment. Numerical analyses demonstrate substantial decreases in total computer time for FOWT structural analyses while maintaining consistent steel design results. The proposed method is uncomplicated, requiring only a simple subprogram modification in a conventional wave load computer program.
KW  - Fast fourier transform; finite element method; floating offshore wind turbine; irregular wave; parallel computing; time-domain wave loads

DO  - 10.32604/cmes.2025.067679