基于细长体公式的Truss SPAR在波流中的运动响应预报方法

利用细长体公式和刚体非线性运动方程建立Truss SPAR在波浪与流中运动响应预报方法。通过波浪自由表面和SPAR中心线方程构造辅助函数,迭代计算Truss SPAR瞬时湿长度。根据SPAR主体形状特点和流场中水质点运动规律,分段高效积分Truss SPAR上的水动力载荷。通过Runge-Kutta-Fehlberg方法求解运动方程,得Truss SPAR在波浪与流中的运动响应。对一座Truss SPAR在不同波流工况中的运动响应进行了预报,结果显示波浪和流使Truss SPAR产生了明显漂移运动和振荡运动,漂移运动的大小与流的方向有关,而振荡运动的幅值与波浪的方向有关。

Numerical Prediction on Motion Responses of Truss SPAR in Waves and Currents by a Slender Formula

A numerical scheme has been built for solving Truss SPAR motions in waves and currents, based on a slender formula and nonlinear motion equations of the rigid body. The wetted length of the Truss SPAR is evaluated by an auxiliary function, which is constructed from the wave free surface and the center line of the Truss SPAR. A subsection plan is used to efficiently calculate the hydrodynamic loads on the hull of the Truss SPAR. Besides, the motion equations are solved by the Runge-kutta-fehlberg method, to acquire the motions responses of the Truss SPAR in flow field. The above numerical scheme is applied to predict the motion responses of a Truss SPAR in waves and currents. The solved results present that the Truss SPAR will make drifting motions and oscillating motions apparently under waves and currents. Moreover the amplitudes of drifting motions and oscillating motions are related to the directions of currents and waves, respectively.