张力腿平台内孤立波载荷及其理论模型

在大型重力式密度分层水槽中，对内孤立波作用下张力腿平台的载荷特性开展了系列实验.基于两层流体内孤立波KdV(Korteweg de Vries)、eKdV(extended KdV)和MCC(Miyata Choi Camassa)理论，建立了张力腿平台内孤立波载荷的理论模型，给出了该理论模型中三类内孤立波理论的适用性条件.研究表明，张力腿平台的内孤立波水平载荷包括立柱与沉箱部分的拖曳力和惯性力，可由Morison公式进行计算，而其竖向载荷主要为竖向Froude Krylov力，可以通过内孤立波诱导动压力在立柱底部及沉箱上下湿表面进行积分计算.系列实验结果表明,在Morison公式中的拖曳力系数与内孤立波诱导速度场的雷诺数之间为指数函数关系，惯性力系数与KC(Keulegan Carpenter)数之间为幂函数关系，而且基于所建立理论模型获得的张力腿平台水平力、竖向力及其力矩的计算结果与系列实验结果吻合.本项研究在系列实验基础上，为海洋工程张力腿平台的内孤立波载荷预报提供了一个实用的理论计算模型.

Internal Solitary Wave Loadsand and Its Theoretical Model for a Tension Leg Platform

A series experiments were conducted to investigate interaction characteristics of internal solitary waves with a tension leg platform in a large-scale gravity type density stratified tank. Based on KdV(Korteweg-de Vries), eKdV(extended KdV) and MCC(Miyata-Choi-Camassa) theories for internal solitary waves in a two-layer fluid, a theoretical model was established for predicting the internal solitary wave loads on a tension leg platform, Besides the applicability conditions for these internal solitary wave theories were presented in order to apply such a load model. It is shown that the horizontal load on the tension leg platform due to the internal solitary wave consists of two parts which are the drag and inertial forces on the vertical column and caisson, and these two forces can be calculated by the Morison formula, while the vertical load is mainly the vertical Froude-Krylov force which can be calculated by integrating the dynamic pressure along with the bottom of the columns, as well as the upper and lower surfaces of all caissons. A series experimental results show that the drag coefficient in the Morison formula follows some exponential function relationships with the Reynolds, while the inertial force coefficient follows power function relationships with KC(Keulegan-Carpenter) numbers. Moreover, the numerical results based on the theoretical predicting model have good agreement with the experimental ones. This research provides a practical theoretical model based on the series of experimental results for predicting internal solitary wave loads on tension leg platforms.