带航速三体渡驳水动力特性频域分析

为了研究带航速三体渡驳在波浪中航行时的水动力特性,以及航速和环境因素对其幅值响应算子的影响,根据势流理论和波浪辐射/衍射理论分析了有航速三体渡驳的波浪激励力及水动力系数,进而利用AQWA求解了三体渡驳的幅值响应算子,得到了不同航速、水深及遭遇浪向条件下三体渡驳各自由度幅值响应算子随波浪圆频率的变化曲线。计算结果表明:航速越大纵荡幅值越小、纵摇峰值越大,水深越浅垂荡幅值越小、纵摇峰值频率越低,当水深吃水比大于20后即可按照无限水深来计算其幅值响应算子;遭遇浪向对各自由度RAOs均有较大影响,其中艏斜浪或迎浪航行对三体渡驳的运动较为有利。

Analysis on hydrodynamic properties of trimaran barge with forward speed in frequency domain

To investigate the hydrodynamic properties of the trimaran barge with forward speed in the wave, and the effects of the velocity and the environmental factors on the response amplitude operators (RAOs) of the trimaran barge, the potential theory and the wave radiation/diffraction theory were employed to analyze the wave exciting forces and the hydrodynamic coefficients. The motions equations of the trimaran barge were solved and RAOs of six degrees of freedom obtained by the general hydrodynamic calculation procedure AQWA. The curves of RAOs with regular wave frequency under different working conditions, such as various speeds, water depths and encounter wave angles, were obtained. The results show that the surge RAOs go down with the increase of the forward speed. However, the pitch peak increases with the increase of the forward speed. The water depth has obvious effects on RAOs, namely the shallow water can decrease the heave RAOs, and the pitch peak frequency goes down with the decrease of the water depth. When the ratio of water depth to the draft is bigger than 20,the water depth can be considered infinite.The encounter angle has big influence on RAOs of each degree of freedom.It is better for the motions that the trimaran barge navigates in the bow sea and head sea.