The application of Fast Fourier Transform (FFT) method in the twin-channel system instability under ocean conditions

Parallel-channel two-phase flow systems under ocean conditions suffer from very serious parallel-channel instability, depending on the inherent characteristics of each channel and operating conditions. The influences of ocean conditions on the instability of parallel channel are very intensive. The trajectory of mass flow is very complex, sometimes even chaos occurs. The traditional methods cannot analyze such curves effectively. In this paper, Fast Fourier Transformation (FFT) method is used to analyze the complex curve of mass flow. Based on this method the oscillation curve can be decomposed. Some basic motions and inherent characteristics can be shown by the decomposition. The accurate analysis of the influence of ocean conditions can be achievable. The onset of inherent parallel-channel instability is also analyzed.