Evaluation of cyclic and monotonic loading behavior of bucket foundations used for offshore wind turbines     

《Applied Ocean Research》2019

Suction caissons are considered as an alternative foundation solution for offshore wind turbines. In the present study, three-dimensional finite element (FE) analyses are performed to assess the behavior of a bucket foundation and soil supporting the bucket under cyclic and monotonic loading conditions. A parametric study is also performed for a wide range of bucket geometries and two different soil densities. The results indicate that bucket geometry and soil properties significantly affect the foundation response due to cyclic loading conditions. The bucket with the smallest geometry installed in medium dense soil exhibits the lowest stiffness in initial loading and then with the progress of cyclic loads experiences lower stiffness compared to the caissons with larger geometries. The sensitivity of the foundation response to the soil density is higher than its geometry. The bucket under the lowest vertical load experiences the lowest stiffness in both virgin loading and during the progress of cyclic loads. The highest soil displacement is observed near the lid at the interior of the bucket. Stresses caused by cyclic loading belong to certain ranges. Additionally, increases in the skirt length result in increases in the stress ranges and shift the range to the right side. With respect to the monotonic loading conditions, normalized diagrams are proposed that can be used for the preliminary design of suction bucket foundations.  相似文献   

Experimental Study on New Multi-Column Tension-Leg-Type Floating Wind Turbine     

ZHAO Yong-sheng  SHE Xiao-he  HE Yan-ping  YANG Jian-min  PENG Tao  KOU Yu-feng 《海洋工程》2018,32(2):123-131

Deep-water regions often have winds favorable for offshore wind turbines, and floating turbines currently show the greatest potential to exploit such winds. This work established proper scaling laws for model tests, which were then implemented in the construction of a model wind turbine with optimally designed blades. The aerodynamic, hydrodynamic, and elastic characteristics of the proposed new multi-column tension-leg-type floating wind turbine (WindStar TLP system) were explored in the wave tank testing of a 1:50 scale model at the State Key Laboratory of Ocean Engineering at Shanghai Jiao Tong University. Tests were conducted under conditions of still water, white noise waves, irregular waves, and combined wind, wave, and current loads. The results established the natural periods of the motion, damping, motion response amplitude operators, and tendon tensions of the WindStar TLP system under different environmental conditions, and thus could serve as a reference for further research.  相似文献   

非定常条件下OWC径向透平冲击式动叶片优化研究          下载免费PDF全文

韩孜乾  刘臻  张晓霞  许传礼  杨鑫 《海岸工程》2022,41(3):198-208

为优化径向透平动叶片的结构型式,有效提高透平工作效率,本文基于Ansys-Fluent软件构建振荡水柱波能发电装置径向冲击式透平的三维瞬态全流域数值模型,通过改变透平动叶片吸力面型式,研究了正弦往复入射气流条件下动叶片厚度差异对透平扭矩、压强等参量的影响及其对透平输入系数、扭矩系数和周期平均效率等非定常性能评价参数的影响。在保证压力面型式不变情况下,研究了5种动叶片厚度分别为7 mm、13 mm、16 mm、19 mm和22 mm的透平在呼气、吸气阶段的非定常工作性能,结果表明：不同动叶片厚度的透平的非定常工作性能存在较大差异,动叶片厚度为13 mm的透平非定常工作性能最优,最大峰值效率可达47.7%。  相似文献   

Modeling of twin-turbine systems with vertical axis tidal current turbines: Part I—Power output     

《Ocean Engineering》2010,37(7):627-637

Recent interest in the tidal current industry has driven development of the prototype from the stand-alone turbine to the twin-turbine system. In this paper, we develop a numerical model to systematically analyze the relationship between the power output and the configuration of a twin-turbine system. First, we present the design principle of the twin-turbine system. We then develop the numerical model for simulating the operation of the system, and validate the model by conducting towing tank experimental tests. We then use the model to predict the power output of the system. The results of this study show that the total power output of a twin-turbine system with optimal layout can be about 25% higher than two times that of a stand-alone turbine. We also discuss the hydrodynamic interaction between the two turbines under different configurations of the system. We conclude that the optimally configured counter-rotating system should be a side-by-side system, and that the optimally configured co-rotating system should have the downstream turbine partially in the wake of the upstream turbine, depending on the detailed configuration of the turbine.  相似文献   

渤海湾北岸海陆风及湍流强度特征分析          下载免费PDF全文

龙强  王锋  王畅  米欣悦 《应用海洋学学报》2020,39(3):303-311

利用渤海湾北岸祥云岛岸基站2017—2018年观测数据和两座梯度测风塔2011—2013年观测资料分别分析了当地海陆风和湍流强度特征,并重点对不同天气系统所致大风条件下的湍流强度特点做了剖析。结果表明:渤海湾北岸海陆风特征明显,昼夜风向主要由SSW向ENE转变,夏季昼夜风向转换尤为显著。整体而言,风速和湍流强度随高度增大分别呈增大、减小趋势,且近海面层湍流强度小于近地层湍流强度。湍流强度具有显著的季节性特征,夏季大、冬季小、春秋季变化不明显,且近海面层湍流强度相对近地层变化平缓。近海面层70 m及以下湍流强度在偏东大风条件下反而比近地层湍流强度大,雷雨大风期间近海面层和近地层均出现湍流强度随高度增大而增大、风速随高度增大而减小的特殊情况,台风靠近风塔时各层风速显著增大、湍流强度变化不明显,但台风中心到达时湍流强度迅速增至峰值,二者时间一致并早于风速最小值出现时间约1 h。近海面层和近地层有8%～10%样本的湍流强度超出了IEC-61400设计标准,建议渤海湾北岸风力发电风机抗湍流参数调整至0. 43～0. 49。  相似文献   

海上风力发电单立柱支撑结构拟静力分析   总被引：1，自引：0，他引：1  

孟珣  侯金林  于春洁  黄维平  李华军 《中国海洋大学学报(自然科学版)》2010,40(2)

海上风电支撑结构不同于一般海洋结构物,它受到复杂的风机气动荷载、机械控制荷载和海洋环境荷载的多重作用。文章针对海上某单立柱风电支撑结构,通过分析其结构固有频率的约束限制以及外环境荷载的动力特性,综合考虑外环境荷载尤其是风机荷载的动力放大影响,给出海上单立柱风电支撑结构的拟静力分析思路。并进行极端及操作工况下支撑结构在风、浪、流环境荷载组合作用的应力计算和强度分析。提出该种结构在使用现有海洋结构物设计规范和风机设计规范时的注意事项。该分析比较结果及结论可作为海上类似风电支撑结构的设计参考。  相似文献   

A Crashworthy Device Against Ship-OWT Collision and Its Protection Effects on the Tower of Offshore Wind Farms     

任年鑫  欧进萍 《中国海洋工程》2009,23(4):593-602

At present,more and more offshore wind farms have been built and numerous projects are on the drawing tables.Therefore,the study on the safety of collision between ships and offshore wind turbines (OWT) is of great practical significance.The present study takes the advantage of the famous LS-DYNA explicit code to simulate the dynamic process of the collision between a typical 3MW offshore wind turbine model with monopile foundation and a simplified 2000t-class ship model.In the simulation,the added mass eff...  相似文献   

Design of a prototype ocean current turbine—Part II: flight control system     

J. VanZwieten  F.R. Driscoll  A. Leonessa  G. Deane   《Ocean Engineering》2006,33(11-12):1522-1551

  相似文献   

Wells turbine with end plates for wave energy conversion   总被引：1，自引：0，他引：1  

Manabu Takao  Toshiaki Setoguchi  Yoichi Kinoue  Kenji Kaneko 《Ocean Engineering》2007,34(11-12):1790-1795

In order to improve the performance of the Wells turbine for wave energy conversion, the effect of end plate on the turbine characteristics has been investigated experimentally by model testing. As a result, it is found that the characteristics of the Wells turbine with end plates are superior to those of the original Wells turbine, i.e., the turbine without end plate and the characteristics are dependent on the size and position of end plate. Furthermore, by using a computational fluid dynamics (CFD), reason of the performance improvement of the turbine has been clarified and the effectiveness of the end plate has been demonstrated.  相似文献   

Comparison between a U-OWC and a conventional OWC     

Paolo Boccotti   《Ocean Engineering》2007,34(5-6):799-805

With an additional vertical duct at the wave-beaten side, an OWC is expected to give some much better performances. This is, essentially, due to two reasons. First, an OWC with the additional vertical duct (U-OWC) has an eigenperiod greater than the eigenperiod of a conventional OWC. Second, the amplitude of the pressure fluctuations on the opening of a U-OWC is greater than the amplitude of the pressure fluctuations on the opening of a conventional OWC (the greater the smaller the wave period is). For the first reason, a U-OWC can give performances better than those of a conventional OWC both with swells and large wind waves. For the second reason, a U-OWC can give performances better than those of a conventional OWC also with small wind waves.  相似文献