Study On Numerical Calculation Of Wave-Induced Motions And Loads For Trimaran

The fluid field around the trimaran becomes much complicated due to the existence of the side hull on both port side and starboard side. Hence the characters of the trimaran change a lot. Compared with the conventional hulls, the trimaran has the broad applicable prospects in both civilian and military areas for its superior performances. Some countries have already carried out the relevant researches and built several full-scale trimarans. Given a super slender trimaran as an example, the wave-induced motions and loads of the trimaran are studied by the combination methods of numerical calculation and verification of model test in this paper. The main work of this thesis are as follows:(1) The Rankine panel method is proposed to compute the time histories of wave-induced motions and loads for the trimaran moving in a harmonic wave with a forward speed. With the same method, the responses of the motions and loads for the trimaran moving in a irregular wave which is assumed as the sum of a set of harmonic waves with the some wave amplitude but the different frequencies and different phase angles are simulated; (2) By using Fourier transform, the time histories of wave-induced motions and loads in time domain are transformed into RAOs in frequency domain. The response spectrums of motions and loads are also calculated in the ten-year return wave state of Mexico Gulf, and afterwards statistical analysis are executed;(3) By the comparison of the results by numerical calculations and model test, the accuracy of the Rankine panel method and numerical results is approved;(4) By numerical method, the influences of the wave-induced motions and loads caused by short creast waves, speeds, the layouts of side hulls (both in transverse and longitudinal directions) and sea depths are studied;(5) By using random theory, the short term predictions as well as the long term predictions are performed for the wave-induced motions and loads of the trimaran.