The influence of fully nonlinear wave forces on aero-hydro-elastic calculations of monopile wind turbines

The response of an offshore wind turbine tower and its monopile foundation has been investigated when exposed to linear and fully nonlinear irregular waves on four different water depths. The investigation focuses on the consequences of including full nonlinearity in the wave kinematics. The linear and nonlinear irregular wave realizations are calculated using the fully nonlinear potential flow wave model OceanWave3D [1]. The linear and nonlinear wave realizations are compared using both a static analysis on a fixed monopile and dynamic calculations with the aeroelastic code Flex5 [2]. The conclusion from this analysis is that linear wave theory is generally sufficient for estimating the fatigue loading, but wave nonlinearity is important in determining the ultimate design loads.     

基于Femap的风帆基座局部强度分析

以上海海事大学教学实习船"育明"轮为对象,研究船舶加装风帆装置的船体结构强度问题,通过局部加强风帆基座和船体连接部分来保证风帆安装部位的结构稳定性。利用Solidworks和Femap软件建立了风帆基座和船体的有限元模型,计算得到该模型在10级风载荷下受风角度从0°~60°的应力和应变。最终结果表明,在10级风载荷下,该船风帆基座和局部加强后的船体的强度符合要求。     

Spar基础浮式风机系泊系统全耦合分析

本文以OC3 Hywind Spar基础浮式风机为研究对象,采用先进的空气动力-水动力耦合时域分析方法,针对其在中国南海某海域风浪流共同作用下,系泊系统、浮式基础运动以及风机与塔桶载荷响应进行分析。对比了定常风与湍流风模型对浮式风机系泊系统、整体运动响应以及风机载荷的影响。计算结果表明：相比于湍流风,采用定常风进行浮式风机系泊系统分析将得到偏于危险的结果,同时浮式风机运动响应与风机载荷结果偏小。本文建议在系泊系统初始设计阶段采用定常风方法进行设计,在系泊分析阶段采用湍流风进行分析,以保证浮式风机长期服役安全。     

一种进一步降低轿车空气阻力的方法

本文首先简要地分析了声激励减阻机理，然后，针对类似桑塔纳车身的模型采用了声激励的方法进行了减低空气阻力的研究，得出了声激励参数，方式和减阻效果的关系，并且对此进行了一定的分析，表明利用声激励方法可以进一步降低此类车身的空气阻力。     

Research on the calculation method of penetration resistance of bucket foundation for offshore wind turbines

The cost of foundations for offshore wind turbines constitutes approximately 35% of the total cost of an offshore wind farm. The bucket foundations show significant potential due to their superior transportation and installation efficiencies compared to pile foundations, leading to potential cost savings for the foundation of up to 30%. For a bucket foundation to be installed successfully, the penetration resistance must be predicted. However, there is currently a lack of clarity on how to select a suitable calculation method for penetration resistance based on known geological parameters to guide construction. In order to evaluate the current methods of calculation for bucket foundation penetration resistance, this study combines theoretical calculation methods with two sets of practical measurement data from the field. The calculation methods of penetration resistance for bucket foundation are first reviewed and categorized. The applicability range of each method and the parameters needed for calculation are given. Next, according to the measured data in the process of penetration of bucket foundation on site, the evolution of compartment pressure, tilt angle, resistance and required suction in the process of penetration are analyzed. Finally, the reviewed methods are compared to the results of two practical projects in order to analyze the differences between them and make recommendations for the calculation technique. The findings can be used as a guide for calculating the bucket foundation's penetration resistance in complex geological conditions.     

风积砂填筑路基施工质量控制

通过工程实践,介绍采用风积砂填筑路基的施工工艺和质量控制过程。     

酒泉至额济纳铁路防沙堤风洞试验数值模拟及积沙试验研究

防沙堤是造价低、使用广泛的工程防沙措施。对三角形和梯形截面防沙堤进行系统对比研究,总结出两种防沙堤的优缺点。通过风洞试验对不同断面形状的防沙堤的流场结构、流场压力分布、积沙情况进行对比研究,然后利用FLUENT数值模拟方法对风洞试验进行验证对比。研究结果和结论:(1)梯形横断面防沙堤迎风侧形成的低速区域宽度大于三角形,梯形迎风侧对沙粒的沉积、滞留作用优于三角形;(2)三角形横断面防沙堤背风侧产生的有效防护宽度大于梯形,防护效果优于梯形;(3)风沙流遇防沙堤阻挡在迎风侧坡脚受阻堆积,积沙达到堤体2/3高度时不再继续堆积增高,一部分向两侧随风流导向两端处,另一部分沿坡越过堤体顶部在落沙坡堆积。准备建设的风沙铁路酒额线及其他交通、民用建筑可以利用以上成果选择防沙堤的形状以达到最好防沙效益。     

船舶受非均匀风力的计算方法

在船舶航海性能及航泊机动的定量分析中,通常以均匀风取代实际的非均匀风,从而影响了定量分析的精度及分析的可靠性。现提出一种新的计算作用在船舶非均匀风力的方法。仿真表明,该方法是可行的。     

风帆辅助推进船舶操纵可控区研究

加装风帆后的船舶在低速时的航行特性有别于无帆情形。为确保低速航行安全,基于MMG非线性运动方程,计算了有、无风帆情况下的船舶操纵可控区。运动方程中的船体水动力系数、舵模块参数等由经验公式得到,帆/船整体气动力系数由基于滑移网格方法的CFD手段获得。计算结果表明:不同帆攻角下的船舶自由操控区不同,通过合理的帆/舵联合操纵,可以扩大风帆辅助推进船舶低速航行的可自由操控区,增强其在风中的抗风能力。     

船舶轨迹运动控制方法改进研究

分析了船舶轨迹控制的直接法和间接法的特点,提出综合航向控制与航迹控制,利用航向差与航迹角度差的变化,调整航向差与航迹角度的相互关系来控制舵角,达到消除航迹偏差的控制目的。通过实船试验,验证了此方法简单实用、控制精度高、灵活性强的特点,特别是在复杂条件下,此法避免了大量的力学分析和算法推演,只考虑各种因素对船舶的实际影响结果,控制效果明显。