Detection of surf-riding behavior of ships in irregular seas
Detection of surf-riding behavior of ships in irregular seas
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DOI：
10.1007/s11071-014-1466-2
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发表时间：
2014-06
影响因子：
5.6
通讯作者：
K. Spyrou;V. Belenky;N. Themelis;K. Weems
中科院分区：
文献类型：
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作者：
K. Spyrou;V. Belenky;N. Themelis;K. Weems
根据对在陡峭的周期性随浪中进行试验的船模的研究，过去已经证实，如果观察到速度达到（瞬时）celebrity值，则通常被认为是“冲浪”的吸引力已经在进行中。这种现象的非线性动力学在理论上也得到了深入的研究;然而，尚不清楚所述简单的唯象检测规则是否对更自然的海浪剖面也有意义。一个实际的问题，促使目前的调查是，是否可以适当量化的持续时间的吸引力，以冲浪骑暴露在一个特定的波环境的总时间的百分比，这样的概率，冲浪骑可以最终计算。在目前的工作中，波动率被定义为波剖面的适当局部性质（例如一定的斜率值）的传播速度。对于不规则的海洋，这导致了瞬时天球的概念。不幸的是，一般来说，瞬时速度不是一个光滑和有界的时间曲线。因此，研究了冲浪问题的一种替代定义的celebrating拟合，其中传播点的配置文件是那些具有局部最大斜率。同时治疗的“波”和“船”的过程中实施，和潜在的条件的基础上，当地的celebrity冲浪骑预测。各种模式的行为之前，并进入冲浪骑观察和讨论。本文是一个步骤的方向发展的概率方法评估的危险现象的冲浪骑和间接的，为类的跨学科现象，服从类似的非线性动力学的评价。
From investigations with ship models tested in steep periodic following waves, it has been conjectured in the past that, if the speed is observed reaching (in transient) the celerity value, attraction toward the condition commonly identified as “surf-riding” is already in progress. The nonlinear dynamics of this phenomenon has been investigated in depth also theoretically; however, it is unknown whether the stated simple phenomenological detection rule is meaningful also for more natural sea wave profiles. A practical question that prompted the current investigation is whether the duration of attraction to surf-riding could be properly quantified as a percentage of the total time of exposure to a specified wave environment, so that a probability of surf-riding could be eventually calculated. Celerity is defined in the current work as the velocity of propagation of a suitable local property of the wave profile, such as a certain value of slope. For irregular seas, this leads to the concept of instantaneous celerity. Unfortunately, instantaneous celerity, in general, is not a smooth and bounded curve in time. An alternative definition of celerity fitting to the problem of surf-riding is thus investigated, where the propagated points of the profiles are those with the locally maximum slope. Simultaneous treatment of the “wave” and “ship” processes is implemented, and the potential of a condition based on local celerity for surf-riding prediction is examined. Various patterns of behavior before and into surf-riding are observed and discussed. The paper is a step in the direction of developing a probabilistic method of assessment for the dangerous phenomenon of surf-riding and indirectly, for the evaluation of the class of cross-disciplinary phenomena that obey similar nonlinear dynamics.