Spar, tension leg platform, and semi-submersibles use heave plates to reduce heave response by increasing heave damping and added mass. Conventional practice is to use a linear damping ratio, which is typically obtained from free heave decay tests or Computational Fluid Dynamics (CFD) simulations. However, with the addition of heave plates, the system damping becomes nonlinear. Understanding such nonlinear damping behavior of spar with circular heave plates in various configurations could be useful in the design of heave compensation devices. Experimental and numerical investigation on heave damping and added mass of a scaled model of spar with a variety of heave plate configurations have been carried out using free heave decay for a range of initial heave displacements. Applicability of the linear and quadratic damping models have been assessed for all configurations. The effects of parameters such as heave plate diameter, location of heave plate above the keel, and spacing between two plates on damping and added mass have also been studied. Flow fields obtained from numerical simulations are presented, and their implication on damping discussed.

翼梁，张力腿平台和半潜式潜水器使用升沉板，以通过增加升沉阻尼和增加质量来降低升沉响应。常规做法是使用线性阻尼比，通常从自由升沉衰减测试或计算流体力学（CFD）模拟获得。但是，通过增加起伏板，系统阻尼变为非线性。了解具有各种构造的圆形升沉板的翼梁的这种非线性阻尼特性可能对升沉补偿装置的设计很有用。使用自由升沉衰减量对一系列初始升沉位移进行了具有多种升沉板构造的翼梁比例模型的升沉阻尼和附加质量的实验和数值研究。线性和二次阻尼模型的适用性已针对所有配置进行了评估。还研究了升沉板直径，隆起板在龙骨上方的位置以及两块板之间的间距等参数对阻尼和附加质量的影响。介绍了从数值模拟获得的流场，并讨论了它们对阻尼的影响。