波浪作用下海底管线的物理模型实验研究

PHYSICAL MODEL TEST OF PIPELINES UNDER WAVE ACTION

本文进行了海底管线受波浪力作用的两种不同比尺的物理模型实验,得出了水平力系数C_(fx)和垂直力系数C_(fz)随Kc数和Re数的变化曲线,并对比了不同比尺物理模型实验的结果。结果对比表明,比尺对波浪力的影响(即粘性影响)是不可忽略的。

Pipelines are often used for offshore oil and gas development and other offshore application. The wave forces acting on pipelines are very important in pipeline designing. So far physical model test is widely used in predicting the wave forces acting on pipelines in engineering. As we know,physical model test can't accord with Froude Law and Eeynolds Law at the same time. If the scale of model changes, while the Kc number of physical model test and real conditions are the same, the Re number of different model scales will be also changed. While the forces acting on pipelines by waves are mainly caused by viscous effect, including surface friction, flow separation, wake and vortex shedding effect. In such case, Re number is an important factor for model test, and the results, usually by small scale model test, cannot directly used in the case of real conditions It requires more studies to resolve the problem of predicting wave forces in real conditions based on the results of small scale model test. Two scale physical model tests of wave forces on pipelines have been done in this study, and the results of two tests are compared. The comparison shows that the small scale model test over estimates the wave forces acting on pipelines according to Froude Law. The regression formulas of horizontal force and vertical force coefficients to Kc and Re number are developed based on the analysis of two tests' data in this paper.