%A TANG Kai, ZHU Ren-Chuan, MIAO Guo-Ping, FAN Ju %T Calculation of Retard Function for Time-Domain Analyzing Floating Body in Waves %0 Journal Article %D 2013 %J Journal of Shanghai Jiao Tong University %R %P 300-306 %V 47 %N 02 %U {https://xuebao.sjtu.edu.cn/CN/abstract/article_40278.shtml} %8 2013-02-28 %X The numerical calculation and comparisons of retard function for time-domain analyzing floating body in waves were conducted by the direct time-domain method (DTM) and the transformation method from frequency to time-domain (FTTM). DTM is a unified and self-contained theory. It needs heavy CPU timeconsuming to obtain retard function by DTM while it is easy and quick by FTTM. For the limitation of frequency band, numerical error is uncertain and may occur when FTTM is used. A wigley-hull-form ship and a cylindrical platform floating in waves were analyzed and verified, and the corresponding retard functions are in good agreement by the two methods. It also indicates FTTM is efficient and practical in dealing with engineering problems. Based on the discussions of the advantage and disadvantages of the two methods, the odd phenomenon due to frequency resonance of ship moving with forward speed was investigated. The influences of various speeds to retard function were also discussed.