三体船主体尺度对其在波浪中动态响应的研究

基于有限元方法,通过仿真计算,比较了三种不同主体尺度下三体船的垂荡、纵摇、横摇运动响应算子。因不同的航行速度对运动算子有一定影响,故分别在低航速和高航速下进行比较。通过不同航速下的垂荡、纵摇、横摇性能对比,得出主体狭长型三体船运动响应性能均最佳,最适合作为三体船主体的尺度。     

三体船侧体位置优化设计研究

基于二维半理论的计算软件TRIMARAN研究了侧体纵向、横向位置的变化对三体船运动响应的影响,同时研究了船体横摇惯性半径对三体船横摇性能的影响,从而提出一套三体船侧体位置优化方案。通过在低速和高速两种情况下,对三体船侧体纵向、横向位置的变化对三体船的运动响应分析,可以看出:低航速下侧体应布置于靠近主体船艏的位置,有利于三体船运动性能的提升,高航速下则应将侧体放置于主体船尾。同时,根据横摇惯性半径对三体船横摇性能的影响研究表明:三体船的横摇半径越小越能增加三体船的横摇稳定性。     

试验养殖工船与液舱晃荡耦合运动时频响应

为分析液舱晃荡和航速对养殖工船运动的影响,采用三维势流理论对一艘试验养殖工船的横摇、纵摇和垂荡进行频域数值计算,并通过Malenica提出的方法考虑液舱晃荡黏性的影响。应用脉冲响应函数法计算系泊工况下的时域耦合运动响应。结果表明,液舱晃荡对横摇运动影响较为显著,横摇固有频率发生偏移;对纵摇谐振幅值影响有限;对垂荡运动几无影响。随着航速的提高,横浪中航行的船舶横摇运动响应没有发生变化,而迎浪中航行的船舶纵摇谐振频率范围内的响应幅值则逐渐增加。试验养殖工船的横摇响应较大,计算结果与实船测量结果比较吻合。     

三体船耐波性预报

应用三维势流理论,计算了三体船在不同航速下垂荡、纵摇、横摇运动频率响应函数。预报了三体船在不规则波中各种海况下航行时的运动和加速度有义值,同时分析了三体船在西北太平洋海区一定海况下的运动特征和规律,最终根据舰船耐波性衡准要求,确定了三体船适合航行的海况与航速,为三体船耐波性方面得出了有价值的参考。     

基于ISIGHT的三体维护船侧体布局多目标优化研究

运用多学科设计优化平台ISIGHT针对三体维护船阻力性能和耐波性能进行侧体布局多目标优化。首先,将各侧体布局方案的CFD计算结果作为样本点,结合三体维护船的特定工作海况,运用谱分析方法预报不规则波中增阻平均值、总阻力值及纵摇、垂荡运动有义值,建立上述参数随侧体布局变化的近似模型,代替数值计算。然后,以最小化不规则波中总阻力值和纵摇、垂荡运动有义值为优化目标,以侧体纵向位置和横向位置为设计变量,采用设置权重和比例因子的方法确定目标函数,将所建近似模型作为数据库,选用多目标遗传算法NSGA-II,进行侧体布局多目标优化。最终,获得阻力性能和耐波性能综合最优的侧体布局方案。从而为海上三体风电维护船的设计和相关船型的性能预报提供参考。     

以Rankine源三维面元法求解三体船纵摇与升沉运动

为对三体船的纵摇与升沉运动进行分析,将三维面元法用于三体船在波浪中的纵摇和升沉计算。依据Rankine源格林函数,基于有航速势流理论建立理论计算模型和数值计算方法,对数学三体船型纵摇、升沉运动响应进行计算,并对计算结果规律进行分析。同时,还对其数值进行模型实验验证。根据计算结果,针对侧体布局对三体船在波浪中纵向运动的影响进行了分析。     

横向补给状态下两船的摇荡运动特性

采用多体水动力学软件AQWA进行横向补给状态下两船在波浪中的频域和时域分析。对高架索道上的恒张力表示为瞬时张力,分析不同航速、浪向角对横摇、垂荡和纵摇方向运动特性的影响,求得两船横向补给时较佳的浪向角和航速,为横向补给时航速和航向的选择提供指导。     

水深对船舶运动和波浪载荷的影响

本文利用简单Green函数法计算二维水动力，特切片法用于有限深水中船舶运动和波载的计算。对实船试算了迎浪航行时几种不同航速和水深的组合，计算结果（垂荡和纵摇响应、舯弯矩和钟前1／4船长处剪力）表明水深的显著影响。水深变浅，垂荡和纵摇响应峰值变小，弯矩和剪力变大，航速越大水深的影响越显著。     

基于Rankine源法的小水线面双体科考船耐波性预报

采用基于三维时域Rankine源方法的水动力分析软件Wasim,对某小水线面双体科考船在不同航速、不同海况与不同浪向下的耐波性进行了计算与分析,重点对不同工况下小水线面双体船横摇、纵摇和垂荡性能进行了研究.研究表明:无航速时,横摇有义单幅值极大值出现在90°浪向,纵摇极大值出现在0°与180°浪向;较高航速时,横摇响应最大单幅值出现在60°与90°浪向,纵摇在30°,150°和180°浪向时明显较大;波浪对连接桥的砰击会显著影响SWATH船的运动响应,使垂荡运动幅值显著增大;随航速的提高,顺浪航行下纵摇运动幅值逐渐减小.     

B.H.型气泡高速艇规则波中纵向运动试验研究

在高速拖曳水池里开展了B.H.型气泡高速艇静水阻力及规则波纵向运动模型试验,研究了气流量、航速、波长、波高等因素变化对B.H.艇波浪中阻力、垂荡、纵摇、垂向运动加速度的影响。探讨了波高变化对饱和气流量的影响。研究结果表明:静水中B.H.艇相对减阻率可达36.25%,绝对减阻率可达20.79%,迎浪规则波中相对减阻率可达32.3%,与静水减阻效果基本相当,波长变化对减阻率的影响甚微。气层并未导致纵向运动性能的恶化,相反在一定航速与波长范围内,艇底气层能改善垂荡与纵摇运动;饱和气流量下,阻力、垂荡、纵摇及重心垂向运动加速度随波高呈非线性变化,航速增大非线性增强,波长增加非线性降低;波浪中饱和气流量随波高呈非线性变化。     

船舶垂荡与纵摇耦合运动频率散射机制研究

针对船舶纵向速度振荡对垂荡与纵摇耦合运动建立运动响应模型,基于弗劳德-克雷洛夫假定,采用切片法推导切片的浮力、阻尼力和惯性力,通过对切片的积分得到了船体垂荡与纵摇的水动力(矩),推导并得到垂荡与纵摇耦合运动响应方程。以某隐身船为实例,初步分析遭遇频率散射强度和散射频率对耦合运动的影响,得到增大散射强度和散射频率可以减弱耦合运动及其剧烈程度的初步结论。     

Experimental and numerical study of the effects of heave plate on the motion of a new deep draft multi-spar platform

The heave motion of a floating structure is critical, as a favorable heave characteristic permits dry tree systems, amongst other benefits. The heave response can be suppressed by installing heave plates. However, the associated hydrodynamic effects, which include viscous damping and added mass, are very complicated. Moreover, there are limited experimental investigations to understand the heave plate effects on actual platform designs. This paper aims to study the abovementioned issue based on a novel deep draft multi-spar (DDMS) platform, for four different configurations (with/without upper and lower heave plates). A set of experiments (free decay, regular and irregular wave tests) are conducted, and compared with time domain and linearized frequency domain analyses. Amongst other things, the investigations and discussions include the added mass and damping coefficients for the platform and heave plates, comparison of experimental and numerical results, and the influence of the heave plates on the surge, heave and pitch motions.     

频率散射对船舶垂荡与纵摇耦合运动的影响

为研究遭遇频率散射现象对船舶垂荡与纵摇耦合运动所造成的影响,以某船为研究对象,假设船舶在顶浪航行,通过船舶纵向速度振荡产生频率散射。基于弗汝德—克雷洛夫假定,推导并得到了垂荡与纵摇耦合运动响应方程。采用切片法计算了耦合运动方程中的水动力系数。通过理论求解方法验证了数值求解耦合运动方程的准确性。同时,还分析了散射强度和散射频率单独对耦合运动的影响,以及两者对耦合运动的综合影响。结果表明,增大散射强度和散射频率可以减弱垂荡和纵摇耦合运动及其剧烈程度。     

基于快速性和耐波性的倒V型船首改型设计

利用CFD数值模拟仿真计算,以减摇减阻为目的,在倒V形船艏的基础上进行船艏改型设计。利用商业软件FineMarine对原型和改型的静水阻力、波浪增阻、纵摇幅值、升沉幅值、波浪中的运动响应等进行数值计算,并对比计算结果,评价改型效果。计算结果表明,改型后静水阻力、规则波中的升沉和纵摇均有不同幅度的减小。     

Truss Spar平台非线性垂荡-纵摇耦合随机运动分析(英文)

Considering the static stability and the change of the displacement volume, including the influences of higher order nonlinear terms and the instantaneous wave surface, the nonlinear coupled heave-pitch motion was established in stochastic waves. The responses of heave-pitch coupling motion for the Truss Spar platform were investigated. It was found that, when the characteristic frequency of a stochastic wave is close to the natural heave frequency, the large amplitude pitch motion is induced under the parametric-forced excitation, which is called the Mathieu instability. It was observed that the heave mode energy is transferred to pitch mode when the heave motion amplitude exceeds a certain extent. In addition, the probability of internal resonant heave-pitch motion is greatly reduced while the characteristic wave frequency is away from the natural heave frequency.     

张力腿平台垂向响应纵摇运动研究（英文）

Tendons vertically moor Tension-Leg Platforms(TLPs), thus, a deep understanding of physical tendon stresses requires the determination of the total axial deformation of the tendons, which is a combination of the heave, pitch, and surging responses. The vertical motion of the lateral sides of the TLP is coupled with surge and constitutes a portion of the pitch motion. Tendons are connected to the sides of the TLP; hence, the total displacement of the lateral sides is related to the total deformation of the tendons and the total axial stress. Therefore, investigating the total vertical response at the sides of the TLP is essential. The coupling between various degrees of freedom is not considered in the Response Amplitude Operator(RAO). Therefore, in frequency domain analysis, the estimated vertical RAO is incomplete. Also, in the time domain, only the heave motion at the center of TLP is typically studied; this problem needs to be addressed. In this paper, we investigate the portion of the pitch motion in the vertical response at the sides of the TLP in both the frequency and time domains. Numerical results demonstrate a significant effect of the pitch motion in the vertical motion of the edges of the TLP in some period ranges.     

Investigation of pitch motion portion in vertical response at sides of a Tension-Leg Platform

Tendons vertically moor Tension-Leg Platforms (TLPs), thus, a deep understanding of physical tendon stresses requires the determination of the total axial deformation of the tendons, which is a combination of the heave, pitch, and surging responses. The vertical motion of the lateral sides of the TLP is coupled with surge and constitutes a portion of the pitch motion. Tendons are connected to the sides of the TLP; hence, the total displacement of the lateral sides is related to the total deformation of the tendons and the total axial stress. Therefore, investigating the total vertical response at the sides of the TLP is essential. The coupling between various degrees of freedom is not considered in the Response Amplitude Operator (RAO). Therefore, in frequency domain analysis, the estimated vertical RAO is incomplete. Also, in the time domain, only the heave motion at the center of TLP is typically studied; this problem needs to be addressed. In this paper, we investigate the portion of the pitch motion in the vertical response at the sides of the TLP in both the frequency and time domains. Numerical results demonstrate a significant effect of the pitch motion in the vertical motion of the edges of the TLP in some period ranges.     

高速轻型穿浪双体船纵向运动改善措施研究

针对在改善高速轻型穿浪双体船(WPC)迎浪中波长与船长接近时纵向运动幅度较大的缺点,采用了理论计算与模型试验相结合的方法,对250 t级穿浪双体船开展了水翼改善纵向运动的理论和试验研究,分析了水翼形式、尺度和安装位置等对纵向运动的影响规律。数值计算和试验结果的比较表明,计及水翼—船体水动力干扰影响的切片理论可满足WPC加水翼后波浪中纵向运动计算的需要,但在纵向运动响应峰值处数值计算结果偏高。模型试验表明,250 t级WPC加装水翼后,迎浪纵摇和垂荡有义幅值可减少20%～30%。     

船舶在纵向波浪中运动的控制方法

船舶主动减摇是目前亟待发展的船舶减摇技术。本文基于船舶在波浪中运动理论,运用MATLAB编程求解带主动减摇鳍的船舶在纵向波浪中的升沉和纵摇运动响应,并据此研究文中给出的主动鳍控制方法减摇效果。通过分析某深V型快速渡轮算例,可以得出明显减摇效果。     

基于N-S方程的航行船舶辐射问题数值模拟

基于N-S(Navier-Stokes)方程,进行了航行船舶辐射问题的数值模拟,包括强制垂荡和强制纵摇的模拟.计算了船舶垂荡和纵摇的附加质量和阻尼.数值模拟中,控制方程--BANS(Reynolds Averaged Navier-Stokes)方程和连续性方程使用有限体积法离散,非线性自由面采用VOF方法处理.文中给出了以不同航速前进的船舶强制垂荡和纵摇的力与力矩,以及船舶垂荡和纵摇的附加质量系数和阻尼系数,并与DUT(Delft University of Technology)的试验数据进行了比较,二者吻合良好.