四浮筒半潜式海上风机基础水动力性能分析

参照三浮筒式OC4半潜式风机基础,设计了四浮筒式浮式风机基础。建立三浮筒式OC4半潜式风机基础与四浮筒式浮式风机基础水动力模型,利用AQWA软件分析四浮筒式浮式风机基础相关水动力参数,并将四浮筒式浮式风机基础与三浮筒式OC4半潜式风机基础进行不同工况下的时域分析对比,探究两者间性能差异。结果表明,四浮筒式浮式风机基础具有良好的水动力性能,相较于三浮筒式OC4半潜式风机基础,其在纵荡、横荡、纵摇、艏摇4个自由度方向上的运动响应以及缆绳张力方面存在优势。     

含月池和输运管的深海采矿船水动力特性研究

深海采矿船是未来人类获取深海矿产资源的重要装备,研究其水动力特性具有重要意义。月池和输运管是影响深海采矿船水动力特性的重要因素。以世界上第一艘超深水采矿船“鹦鹉螺新纪元”号为研究对象,基于三维势流理论,分析月池尺寸、输运管长度及内径对采矿船水运动特性的影响。结果表明：月池开口会使采矿船垂荡、纵荡和纵摇运动出现共振峰,峰值随着开口尺寸的增加而增大,其中垂荡运动峰值可增加将近2倍;输运管的存在会明显改变采矿船横摇运动固有周期,增大垂荡运动峰值,降低横摇运动峰值,对横荡和纵荡运动的影响亦较大,当输运管长度为 5 000 m,内径为0.480 5 m时,横荡和纵荡响应峰值能够达到无输运管时的3倍以上。通过探究月池开孔和输运管不同参数对采矿船运动的影响,为深海采矿船月池和输运管设计提供一定的借鉴和参考。     

摆动尾鳍水动力性能的试验和数值研究

鱼类能够在水下高速度、低噪音、高效率地游动。鱼类出色的推进性能通过其摆动尾鳍实现。这种摆动尾鳍推进方式已经用在了水下无人航行器上。因此研究摆动尾鳍的水动力性能是非常有意义的。对摆动尾鳍的推进水动力性能进行了详尽的研究。设计、装配了一套仿尾鳍推进系统,并对其进行了相应的水动力试验。在试验中研究了运动参数对摆动尾鳍水动力性能的影响。与此同时,采用基于雷诺平均N-S方程的数值方法对摆动尾鳍的水动力性能进行了研究。在数值计算中采用了k-ωSST湍流模型和有限体积法。数值计算结果和水动力试验结果进行了比较。对尾鳍表面的压力分布和流场中的尾涡结构进行了分析。水动力试验和数值计算都表明摆动尾鳍可以产生推进力和较高的推进效率。     

一种适用于深水浮式海洋平台结构的新型系泊系统设计及水动力性能分析

作为浮式结构最常采用的两种系泊方式,悬链式系泊和张紧式系泊皆存在不足。本文提出了一种新型系泊系统,并以一深水FPSO为例,采用完全时域耦合分析方法,对不同工作水深情况下的浮体及新型系泊系统的运动性能进行了数值模拟,并将该新型系泊系统的仿真结果与传统的张紧式系泊系统进行了比较,分析了新型系泊系统在浮体运动性能、缆索张力等方面的改善,同时探讨了该新型系泊系统的最佳工作水深。     

平潭近岸海域浮子漂移轨迹及其数值模拟

平潭近岸海域岸线曲折,周边岛礁众多,海底地形复杂,是福建省海难事故的高发区.本研究建立了平潭近岸海域海上目标物漂移轨迹的预测系统,该系统通过风场和流场的数值模型获取海面动力环境信息,采用拉格朗日算法实现对海上目标物漂移轨迹的预测追踪.其中海流模型采用ROMS（regional ocean modeling system）模型构建,模型水平方向上最高分辨率为100m,垂向上分为16层,并考虑干湿边界,以体现复杂海岸线和水深地形.通过验证分析,潮位、流速和流向的模拟平均绝对误差分别为0.20 m、0.12 m/s和26°.通过平潭近岸2个浮子实验,结果表明,浮子漂移过程中受潮流和局地地形的影响明显,对漂移模型在平潭近岸海域的适用性进行初步验证,浮子模拟轨迹与实际漂移过程基本吻合,模拟时段内最大偏差距离为2.8km,系统可以为平潭近岸海域海上突发事故应急决策提供参考.     

Experimental Study on Allowable Berthing and Mooring Conditions of An Oil Tanker

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Hydrodynamic effect of the regulation project of Yangtze River deepwater channel downstream of Nanjing

A two-dimensional flow numerical model of the tidal reaches, which total length is more than 700 km, is established from Datong to the Yangtze River estuary. The tidal levels, velocities, diversion ratios and dynamic axes before and after the separate regulation of each reach and combined regulation of all reaches are obtained. The comparative analysis shows that the regulation project of a separate reach basically has no impact on velocity distributions and variations of diversion ratios of upper and lower reaches, the variations of dynamic axes are only within the local scope of the project. The regulation project of a separate reach also has less impact on the water level in the lower adjacent reaches, but will make the water levels in the upper reaches rise. After the implementation of the regulation projects for all reaches, the rise of water level in the upstream reaches will have a cumulative impact.     

基于LabVIEW的自升沉式潜标模拟测试系统设计

自升沉式潜标正式布放使用前应进行大量的测试试验工作。为了能够在岸边或实验室对潜标的各项性能进行验证和调试工作,开发了基于LabVIEW的潜标模拟测试系统。该系统充分利用虚拟仪器的特点,采用模块化编程技术,利用软件模拟潜标在水下的各种运动状态及传感器感应的测量参数变化,或通过对现场测量数据的回放查找分析潜标系统本身存在的缺陷,实现潜标不下水或少下水就可以进行全面测试的目的。实验结果表明,利用模拟测试系统可以进行固定值、极值和连续变化值模拟,能够缩短设备开发周期,优化系统控制方案,对提高产品质量具有非常重要的作用。     

Hydrodynamic Effect of the Regulation Project of Yangtze River Deepwater Channel Downstream of Nanjing

A two-dimensional flow numerical model of the tidal reaches, which total length is more than 700 km, is established from Datong to the Yangtze River estuary. The tidal levels, velocities, diversion ratios and dynamic axes before and after the separate regulation of each reach and combined regulation of all reaches are obtained. The comparative analysis shows that the regulation project of a separate reach basically has no impact on velocity distributions and variations of diversion ratios of upper and lower reaches, the variations of dynamic axes are only within the local scope of the project. The regulation project of a separate reach also has less impact on the water level in the lower adjacent reaches, but will make the water levels in the upper reaches rise. After the implementation of the regulation projects for all reaches, the rise of water level in the upstream reaches will have a cumulative impact.     

A Modified Quasi-Static Method for CALM System Analysis

The quasi-static analysis method introduced by API RP 2P is well known and accepted as a very useful mooring analysis method. In the early design stage, this method is widely used for preliminary analysis and mooring parameter selection. However, the quasi-static method of API RP 2P is developed for single-floating-body condition, i. e., only one floating body is considered in the computation procedure. Difficulties arise when it is used for the analysis of a CALM system, which is comprised of two floating bodies (tanker and buoy). This paper presents an analysis procedure for a two-floating-body system based on the quasi-static procedure of API RP 2P with some modifications reflecting special characteristics of the CALM system. Finally, the analysis results of a CALM system are given to illustrate the use of this procedure.     

渤海风暴减水特征及其对深水航路影响的数值模拟

利用环渤海9个沿岸站近10a潮位资料分析渤海海域的风暴减水特征,结果表明:渤海年均出现50cm和100cm风暴减水分别超过30d和6d,每年的9月至翌年4月份风暴减水最为频繁;建立了一套精细化天文潮-风暴潮耦合模型用于渤海深水航路的潮位预报,各站天文潮模拟验证的平均均方根误差为18.5cm,由此计算得到航路代表点的潮汐特征值并作潮汐预报;后报模拟了近10a重大风暴减水过程,模拟与实测吻合较好,说明该耦合模型可为该航路的潮位预报提供有益参考。     

新型圆筒型FPSO串靠外输作业耦合水动力响应分析

针对1 000 m水深作业的新型圆筒型浮式生产储卸油系统（FPSO）,选择多点系泊FPSO和穿梭油轮串靠外输方案,分析串靠方案在中国南海的可行性。FPSO和穿梭油轮作业时两者之间相互影响的研究较为重要,通过ANSYS-AQWA建立水动力耦合分析模型,基于多浮体水动力学方法进行时域耦合仿真模拟。在FPSO作业海况下,分析了串靠外输时系泊锚链及系泊大缆的张力特性和两浮体的运动响应,对大缆的长度和刚度参数变化进行了分析。结果表明：串靠外输方案满足新型圆筒型FPSO的作业环境。随着系泊大缆长度增加,其张力最值逐渐减小,FPSO和穿梭油轮的最小间距逐渐增大。两浮体最小距离稳定在83 m左右。随着系泊大缆刚度增加,其张力最值增大,相比于大缆长度,大缆刚度对耦合系统的影响较弱。     

Bearing capacity of offshore umbrella suction anchor foundation in silty soil under varying loading modes

Considering the current disadvantages of present offshore wind turbine foundations, a novel anchor foundation with skirt and branches is proposed, called offshore umbrella suction anchor foundation (USAF). A series of experiments and numerical simulations were performed to explore the bearing capacity of the USAF under various kinds of loading modes. The bearing characteristics and the anchor–soil interactions are described in detail for horizontal static loading, horizontal cyclic loading, and an antidrawing (pullout) test in silty soil. In the static loading test, the load–deflection of the anchor under step loading was analyzed and the normalized curve of the load–deflection was obtained to determine the ultimate horizontal bearing capacity of the anchor under normal working conditions. Under horizontal cyclic loading, the relationship between the plastic cumulative deformation and cyclic number was determined. In addition, the responses of USAF were investigated for a low wave frequency and storm surges. In the drawing test, it was found that a “segmentation phenomenon” occurred during the test. Moreover, a method to identify the maximum antidrawing load of USAF was provided based on dynamic mechanics. The numerical results show that the use of anchor branches and skirt can enhance the bearing performance of USAF to a certain degree. However, the anchor branch has a slight positive influence on the bearing performance improvement. The USAF is not only similar to a stiff short pile, but a rotation occurs. The failure envelope under composite loading (V-M) was obtained and the changes associated with changes in the aspect ratio of the internal compartment were clarified.     

基于准动态模型的提油作业拖轮适用性分析

目前,由于串靠外输方式具有对船舶吨位差异及装载状况要求小、海况适应力强、系泊力小、解脱迅速等优点,而被广泛运用于浮式生产储卸油平台(FPSO)外输作业中。串靠提油作业时,位于穿梭油轮尾部的拖轮能够提供的最大有效拖力直接影响到了作业的安全性。为完善串靠提油作业时所需拖轮拖力的研究,提出更加合理的拖轮选型理论依据,就需要对拖力进行数值计算。首先,对FPSO与穿梭油轮串靠外输系统绕系泊单点旋转时所受风、浪、流等环境载荷进行全面考虑,建立了准动态受力平衡模型;然后,运用经验公式及AQWA软件计算出环境载荷大小,并依据计算结果拟合出环境载荷曲线;最后,配合受力平衡方程求解出能够保障作业安全进行所需的最小拖力。依照此方法计算所得拖力选取的拖轮能够兼顾作业安全性和使用经济性。