Evaluation of Geometrical Influence on the Hydrodynamic Characteristics and Power Absorption of Vertical Axisymmetric Wave Energy Converters in Irregular Waves

IF 2 3区 工程技术 Q2 ENGINEERING, MARINE
Wanchao Zhang, Yang Zhu, Shuxu Liu, Jianhua Wang, Wentian Zhang
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引用次数: 0

Abstract

Abstract To obtain the mechanical energy of waves from arbitrary directions, the vibration absorbers of wave energy converters (WEC) are usually vertically axisymmetric. In such case, the wave-body interaction hydrodynamics is an essential research topic to obtain high-efficiency wave energy. In this paper, a semi-analytical method of decomposing the complex axisymmetric boundary into several ring-shaped stepped surfaces based upon the boundary approximation method (BAM) is introduced and examined. The hydrodynamic loads and parameters, such as the wave excitation forces, added mass and radiation damping of the vertical axisymmetric oscillating buoys, can then be achieved by using the new boundary discretisation method. The calculations of the wave forces and hydrodynamic coefficients show good convergence with the number of discretisation increases. Comparison between the constringent results and the results of the conventional method also verifies the feasibility of the method. Then, simulations and comparisons of the hydrodynamic forces, motions and wave power conversions of the buoys with series draught and displacement ratios in regular and irregular waves are conducted. The calculation results show that the geometrical shape has a great effect on the hydrodynamic and wave power conversion performance of the absorber. In regular waves, though the concave buoy has the lowest wave conversion efficiency, it has the largest frequency bandwidth for a given draught ratio, while in irregular waves, for a given draught ratio, the truncated cylindrical buoy has the best wave power conversion, and for a given displacement of the buoy, the concave buoy shows the best wave power conversion ability.
垂直轴对称波能转换器在不规则波浪中水动力特性和吸能的几何影响评价
摘要为了从任意方向获取波浪的机械能,波能转换器的吸振器通常是垂直轴对称的。在这种情况下,波体相互作用流体力学是获得高效波能的重要研究课题。本文介绍了一种基于边界近似法(BAM)的将复杂轴对称边界分解为若干环形阶梯曲面的半解析方法,并对其进行了检验。利用新的边界离散化方法,可以得到垂直轴对称振荡浮标的波浪激振力、附加质量和辐射阻尼等水动力载荷和参数。随着离散次数的增加,波浪力和水动力系数的计算具有较好的收敛性。将压缩结果与常规方法的结果进行比较,验证了该方法的可行性。然后,对具有系列吃水比和排水量比的浮标在规则波和不规则波中的水动力、运动和波能转换进行了模拟和比较。计算结果表明,吸波器的几何形状对吸波器的水动力和波浪能转换性能有很大影响。在规则波浪中,凹形浮标的波浪转换效率最低,但在一定吃水比下,其频率带宽最大;而在不规则波浪中,在一定吃水比下,截形圆柱浮标的波浪能转换效果最好,在一定位移下,凹形浮标的波浪能转换能力最好。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
Polish Maritime Research
Polish Maritime Research 工程技术-工程:海洋
CiteScore
3.70
自引率
45.00%
发文量
20
审稿时长
>12 weeks
期刊介绍: The scope of the journal covers selected issues related to all phases of product lifecycle and corresponding technologies for offshore floating and fixed structures and their components. All researchers are invited to submit their original papers for peer review and publications related to methods of the design; production and manufacturing; maintenance and operational processes of such technical items as: all types of vessels and their equipment, fixed and floating offshore units and their components, autonomous underwater vehicle (AUV) and remotely operated vehicle (ROV). We welcome submissions from these fields in the following technical topics: ship hydrodynamics: buoyancy and stability; ship resistance and propulsion, etc., structural integrity of ship and offshore unit structures: materials; welding; fatigue and fracture, etc., marine equipment: ship and offshore unit power plants: overboarding equipment; etc.
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