Numerical simulation of wave energy converters using Eulerian and Lagrangian CFD methods
Numerical simulation of wave energy converters using Eulerian and Lagrangian CFD methods
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发表时间：
2010
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通讯作者：
J. Westphalen;D. Greaves;A. Hunt-Raby;C. Williams;P. Taylor;Z. Z. Hu-Z.;P. Omidvar;D. Causon;C. Mingham;P. Stansby;B. Rogers
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作者：
J. Westphalen;D. Greaves;A. Hunt-Raby;C. Williams;P. Taylor;Z. Z. Hu-Z.;P. Omidvar;D. Causon;C. Mingham;P. Stansby;B. Rogers
在过去的几年中，已经提出了许多波浪能转换器（WEC）的概念。所有这些都是为了在平均海况下以具有竞争力的经济速度发电，并在极端波浪条件下生存。由于大多数海上波浪能装置的复杂性及其在不同海况下的运动响应，物理水槽试验是WEC设计的常见做法。全尺寸试验也是必要的，但费用昂贵，只有在设计优化后才考虑。计算流体动力学（CFD）现在被认为是海洋工程中传统物理测试技术的重要补充。一旦针对问题进行了适当的校准和验证，CFD就可以提供高密度的测试数据，并在合理的时间范围内得出结果，以帮助对设备进行设计变更和改进。在EPSRC资助的研究项目“海上波浪能装置的极端波浪载荷：分层团队方法”中，使用不同的欧拉和拉格朗日CFD技术对两个WEC Pelamis和Manchester Bobber进行了研究。这两种装置都漂浮在水面上，通过波浪的运动发电。由于系泊系统，Pelamis的整体运动受到限制，但允许单个节段以6个自由度移动，并与波浪和相邻节段相互作用。Manchester Bobber的动力学包括以阵列布置的浮子的名义上的垂直运动，以及浮子和波浪之间的高度复杂的相互作用。使用不同的CFD技术对Pelamis和Manchester Bobber的全动态模拟进行了两个测试用例。问题涉及规则波与不同淹没深度的固定水平圆柱体之间的相互作用。结果与实验数据进行比较，以校准CFD代码。最后给出了水面上振动锥体的流固耦合计算结果。这个问题的复杂性相当高，因为它涉及到轴对称体的刚体运动。运动不是线性的，而是作为高斯聚焦波包生成的。复杂的射流效应发生在水和物体表面的相交处。这些和结构上的力进行了讨论。四种不同的CFD代码应用于模拟测试用例：光滑粒子流体动力学，笛卡尔切割单元方法的基础上的人工压缩性方法与冲击捕获的接口，和两个压力为基础的Navier-Stokes代码，一个使用有限体积和其他控制体积为基础的有限元方法。?? 2010年，国际海洋和极地工程师协会（ISOPE）。
During the last years many concepts of wave energy converters (WEC) have been proposed. All are designed to generate energy at competitive economic rates in average sea states and also to survive extreme wave conditions. Due to the complexity of most offshore wave energy devices and their motion response in different sea states, physical tank tests are common practice for WEC design. Full scale tests are also necessary, but are expensive and only considered once the design has been optimised. Computational Fluid Dynamics (CFD) is now recognised as an important complement to traditional physical testing techniques in offshore engineering. Once properly calibrated and validated to the problem, CFD offers a high density of test data and results in a reasonable timescale to assist with design changes and improvements to the device. Within the EPSRC funded research project "Extreme Wave Loading on Offshore Wave Energy Devices: a Hierarchical Team Approach" the two WECs Pelamis and the Manchester Bobber are investigated using different Eulerian and Lagrangian CFD techniques. Both devices float on the water surface and generate the electricity from the motion of the waves. Pelamis' overall movement is limited due to the mooring system, but the individual segments are allowed to move in 6 degrees of freedom and interact with the waves and the adjacent segments. The dynamics of the Manchester Bobber comprise the nominally vertical motion of the floats, which are arranged in an array, and the highly complex interactions between the floats and the waves. Two test cases leading towards simulation of the full dynamics of Pelamis and the Manchester Bobber have been modelled using different CFD techniques. The problems involve the interaction between regular waves and fixed horizontal cylinders of different levels of submergence. Results are compared with experimental data to calibrate the CFD codes. Furthermore, results for the fluid-structure interaction of an oscillating cone on the water surface are presented. The complexity of this problem is rather high, as it involves rigid body motion of an axisymmetric body. The motion is not linear, but is generated as a Gaussian focused wave packet. Complex jet-effects occur at the intersection of water and body surface. These and the forces on the structure are discussed. Four different CFD codes are applied to simulate the test cases: Smoothed Particle Hydrodynamics, a Cartesian Cut Cell method based on an artificial compressibility method with shock capturing for the interface, and two pressure-based Navier-Stokes codes, one using a Finite Volume and the other a control volume based Finite Element approach. ?? 2010 by The International Society of Offshore and Polar Engineers (ISOPE).