ABSTRACT

Many wave energy converter (WEC) designs emerging over the recent years are floating cylindrical geometries with position-keeping mooring system. However, the dynamic stability of these novel floating structures under random sea states has not been investigated adequately. The Melnikov function model and the Markov process model are two efficient approaches providing quantitative predictions of capsizing. In this study, application of the two methods to a moored floating cylinder representing a generic WEC, has been explored to predict the risks of pitchpoling under random excitation. Using the Melnikov approach, the rate of phase space flux was evaluated to quantify the dynamic stability. This approach is compared with the Markov approach, which evaluates the mean first escape (capsize) rate to quantify the dynamic stability. The two methods are investigated through studies using various parameters. The similarity of their results and the differences of their approximations will be explored.

摘要

近年来出现的许多波浪能转换器 (WEC) 设计都是具有位置保持系泊系统的浮动圆柱形几何形状。然而，这些新型浮动结构在随机海况下的动态稳定性尚未得到充分研究。Melnikov 函数模型和 Markov 过程模型是提供倾覆定量预测的两种有效方法。在这项研究中，已探索将这两种方法应用于代表通用 WEC 的系泊浮筒，以预测随机激励下的螺距风险。使用 Melnikov 方法，评估相空间通量的速率以量化动态稳定性。将此方法与马尔可夫方法进行比较，马尔可夫方法评估平均首次逃逸（倾覆）率以量化动态稳定性。通过使用各种参数的研究来研究这两种方法。将探讨它们结果的相似性和它们的近似值的差异。