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1.
《海洋技术学报》2023,(3)
深海中蕴藏着丰富的矿产资源，深海采矿船是深海采矿的重要装备，通过动力定位系统控制采矿船的海上位置，动力定位系统由若干推进器组成。采矿船在海上受到风浪流作用，推进器一旦失效极易发生采矿船运动失控等安全事故，本文研究推进器不同失效方式下动力定位性能，分析推进器不同失效方式动力定位功能的损失。根据势流理论计算波浪载荷，数值模拟深海采矿船不同位置的单个推进器失效和多个推进器失效方式下的时域运动响应，对比各种失效方式对深海采矿船纵荡、横荡、艏摇三个自由度运动的影响，分析各种失效方式对剩余推进器推力的影响。研究结果表明：采矿船空载90°浪向，推进器不同失效模式对于纵荡运动影响远小于对横荡和艏摇运动影响，船艉单推进器失效对于纵荡和艏摇动力定位的影响大于两个推进器失效影响；对于采矿船多自由度运动动力定位两个推进器失效大于单推进器失效影响；一侧两个推进器或两侧推进器同时失效，对动力定位的影响相同，对于横荡运动的影响最大。本文揭示了深海采矿船推进器失效对于采矿船运动的影响程度和机理，对于深海采矿船的安全作业具有指导意义。 相似文献
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随着船舶大型化和港口建设深水化发展，外海不同周期波浪作用下大型系泊船泊稳问题与小型系泊船相比出现了新的特点。为此，利用数值模型方法研究了在不同入射角度和周期的涌浪作用下港内大型系泊船的水动力响应，针对系泊船的泊稳情况探讨了船舶的运动规律和运动特性。研究发现，在涌浪周期较大的情况下，限定波高的泊稳标准不足以用来确定系泊船的正常作业条件，港内泊船的水平运动（纵荡、横荡和艏摇）极易超出运动标准值并影响装卸作业效率，并且船舶的水平运动表现出主要由次重力波主导的低频运动特性，而垂直运动（垂荡、横摇和纵摇）表现出主要由短波主导的波频运动特性。 相似文献
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月池内流体存在活塞和晃荡两类振荡现象。基于线性势流理论,推导了波浪斜向入射下,直墙前矩形月池辐射和绕射问题的解析解。通过分离变量法和特征函数展开法求解了速度势函数,根据边界条件来确定速度势函数中的未知系数,由速度势函数计算斜向波与矩形月池相互作用的水动力系数和波浪激励力,对它们的变化规律进行了分析讨论,研究了底部开口大小、波浪入射角度对矩形月池水动力特性的影响以及直墙远近对波浪力的影响。结果表明,月池底部开口大小对流体水平作用的影响较小,而对流体垂直作用的影响较大;波浪入射角度的变化对矩形月池横荡和横摇运动时的水动力特性有一定的影响;在一定条件下,直墙的存在会使得月池在水平方向所受到的波浪力比开敞水域中的要大。 相似文献
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垂荡板对半潜式风机基础水动力性能有极大的影响，从而影响基础拖航安装过程的安全。为了研究垂荡板对半潜式基础拖航过程中运动响应的影响，建立了拖缆—WindFloat浮式风机半潜式基础拖航系统模型。首先，基于三维势流理论，采用AQWA开展了拖航系统的频域水动力分析，分析了垂荡板的尺寸及形状对基础水动力性能的影响规律；进一步采用时域方法对拖航系统的运动响应进行分析，探究了垂荡板的尺寸及形状在不同浪向下对基础运动响应的影响规律。结果表明：垂荡板能有效抑制基础的垂荡RAO，但垂荡板形状对基础的水动力性能无明显影响；具有圆形垂荡板的半潜式基础在拖航过程中的运动性能略优于六边形垂荡板，在原设计基础上继续增大垂荡板尺寸对基础运动响应的抑制效果呈现先增大后减小的趋势，说明半潜式风机基础存在一个最优的垂荡板尺寸。 相似文献
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探讨SPAR平台在波流组合作用下的运动响应机理。运用Matlab程序分析了SPAR平台产生内共振的运动过程,运用刚体动力学理论建立了平台垂荡-纵摇耦合方程,对波流共同作用下Spar平台的垂荡、纵摇运动进行数值模拟,结果表明:流的加入对于内共振的影响并不明显;同时采用AQWA软件研究了流的加入对于纵荡二阶慢漂力的影响,研究发现,当波流同向时能大大增加Spar平台的纵荡运动,而波流反向时却能明显削弱纵荡运动。本文研究成果对于指导深海浮式结构设计开发具有一定的理论借鉴作用。 相似文献
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概念性地设计了一种新型半潜式海上风力机基础,确定了结构的型式和尺寸,对风浪联合作用下不同工况的风力机基础稳性进行了校核.考虑黏性阻尼和二阶波浪力的作用,计算分析了风力机基础的水动力系数、幅频运动以及动力响应特性.结果表明,经过改进的新型风力机基础具有良好的稳性和水动力性能,特别是在垂荡性能上有大幅的提升.波浪入射角度对垂荡的影响不大,但对其他自由度RAOs影响较大.垂荡、横摇和纵摇RAOs均存在一个主峰值和次峰值,但峰值周期均远离波能集中区.此外还发现,不同工况下风浪入射角对风机系统的动力响应和系泊力均有较大影响,相对于工作工况,极端工况下所受风荷载较小,但是系泊力更大. 相似文献
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考虑内流的作用,研究缓波形立管在海洋环境荷载作用下的非线性静动力力学性能。采用细长柔性杆理论,建立缓波形立管运动方程,利用有限元法进行离散,运用Newton-Raphson法和Newmark-β法分别对立管进行静动力分析,编制缓波形立管计算分析程序LWRNM,研究缓波形立管在海流、内流、浮体漂移与运动作用下的结构响应。结果表明:随着海流从x负向变成x正向和流速的增大,缓波形立管线形变缓,有效张力增大,弯曲曲率的极值减小;随着内流流速的增加,缓波形立管的固有频率下降;随着顶部浮体从近端向远端漂移,缓波形立管的有效张力增大,弯曲曲率的极值减小;纵荡和垂荡作用下,缓波形立管的顶部有效张力变化周期与浮体激励周期相同,横荡作用下,顶部有效张力变化周期为浮体激励周期的二分之一,垂荡作用下,缓波形立管顶部有效张力变化幅值最大,纵荡作用下次之,横荡作用下最小。 相似文献
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双体船由于其优良的快速性和横稳性等特性，在民用和军用中应用广泛。针对无限水深下迎浪、斜浪中自由运动的WigleyⅢ双体船，利用线性势流软件WAMIT，通过调整片体间距，对双体船的水动力系数及船体运动响应进行计算和比较，分析不同片体间距的双体船的耐波性。结果发现，片体间距较小的双体船附加质量系数较小，垂荡、纵摇阻尼系数显著增大，垂荡和纵摇运动响应幅值增大，且附加质量系数为负值时的系数绝对大小和频率范围随着片体间距的减小而变大。同时，片体间距越小的双体船间的流体干扰作用令自由面运动响应更加剧烈，迎浪下船体垂荡运动响应略有增大，纵摇运动响应略有减小；而斜浪下垂荡、纵摇、横摇运动响应均增大，船体的耐波性较差。当片体间距较大，在某一频率入射波下，双体船运动响应接近为零，且该频率随着片体间距的增大而减小。另外说明，相较于阻尼系数，附加质量系数对船体运动的影响更大。 相似文献
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以新型激光雷达浮标系统为研究对象,基于ANSYS/AQWA开展了激光雷达浮标系统运动响应特性数值研究,研究了浮标吃水深度、形状参数对于激光雷达浮标运动响应的影响规律,分析了附加质量、辐射阻尼、运动响应RAO及一阶、二阶波浪力等水动力参数。采用时域分析方法对不同风浪流荷载入射角度下的激光雷达浮标锚泊系统张力特性进行了计算分析。研究结果表明:随着浮标吃水深度的增加,浮标纵荡方向响应无明显变化,垂荡响应显著增大;随着浮标底部圆台直径的增大,浮标纵荡方向响应变化较小,而圆柱形浮标垂荡运动响应显著大于圆台形浮标;当浮标系泊锚链发生松弛—张紧状态变化时易出现极端张力,且极端张力出现的幅值和频率随有效波高的增大和谱峰周期的减小而增大。 相似文献
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The present paper describes a mathematical model in which the fluid motion inside a U-tank is nonlinearly coupled to the heave, roll and pitch motions of the ship. The main purpose of the investigation is centred on the control of roll motion in the case of parametric resonance in longitudinal waves. A transom stern small vessel, known to be quite prone to parametric amplification, is employed in the study. Four tank designs are employed in order to study the influence of tank mass, tank natural frequency and tank internal damping on the control of parametric rolling at different head seas conditions. Additionally, the influence of the vertical position of the tank is also investigated. The main results are presented in the form of limits of stability, with encounter frequency and wave amplitudes as parameters. Distinct dynamical characteristics are discussed and conclusions are drawn on the relevant parameters for the efficient control of the roll amplifications in head seas. 相似文献
12.
共振运动是深海浮式平台设计的关键考虑因素之一,对海洋平台的作业具有重要影响。采用半潜式平台运动的非线性耦合数学模型,考虑浮筒和横撑出入水以及垂荡、横摇和纵摇运动耦合对平台浮力和恢复力的影响,研究半潜式平台非线性共振运动特性,以及不规则波浪参数对运动的影响。研究表明:在非线性耦合运动和浮力变化的影响下,半潜式平台纵摇和垂荡运动的固有周期会随运动幅值的增大而逐渐减小,且最终趋于稳定,对纵摇运动周期的影响更为显著;非线性效应会使半潜式平台产生显著的低频纵摇共振响应,以及共振频率漂移的现象,且受随机种子和波浪周期的影响较小。 相似文献
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Large volume semi-submersible units may present significant wave induced resonant motions in heave, roll and pitch. Evaluating the slow motions of such systems is important from the initial stages of their designs and therefore requires a model that is both accurate and expedite enough. In the present article, different options for modeling the second-order hydrodynamic forces and induced motions are discussed using as a case-study the PETROBRAS 52 unit—P-52. Computations of the low frequency forces are performed in the frequency domain by means of a commercial Boundary Element Method (BEM) code. Different hydrodynamic approximations are tested and evaluated by directly comparing the predicted responses with those measured in small-scale tests performed in a wave-basin. From the results obtained in theses comparisons, a methodology based on a white-noise approach of the force spectrum is proposed. The validity of such approximation is attributable to the typically low damping levels in heave, roll and pitch motions. Furthermore, results also indicate that the second order forces may be calculated disregarding the free-surface forcing components, an option that helps to reduce the computational burden even more, rendering the procedure suitable for preliminary design calculations. 相似文献
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基于细长体水动力模型比较了Truss Spar平台在波流联合作用下运动响应预报的三种方法。分别采用波流耦合、速度叠加及力叠加计算Truss Spar平台在波流联合作用下的水动力载荷,根据流场水质点运动规律和Truss Spar外部形状特点,分段高效计算水动力载荷。利用Runge-Kutta-Fehlberg方法求解刚体非线性运动方程得Truss Spar在波流场中的运动响应。研究结果表明力叠加法所预报的Truss Spar纵荡和纵摇运动明显大于其他两种方法的相应运动响应预报结果,而波流耦合法与速度叠加法所预报的纵荡与纵摇运动响应幅值相当,三种方法所预报的垂荡运动响应的大小取决于具体波流参数。 相似文献
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The present paper describes an investigation on the relevance of parametric resonance for a typical fishing vessel in head seas. Results for different Froude numbers are discussed based on experimental, numerical and analytical studies.The first region of resonance is investigated. Distinct wave amplitudes are considered. Some intense resonances are found to occur. The paper compares the experimental results with non-linear time simulations of the roll motion. Very good agreement is found, even when large motions take place.Finally, in order to analyze the experimental/numerical results, analytic consideration is given to distinct parameters affecting the dynamic process of roll amplification. The influence of heave, pitch, wave passage effect, speed and roll restoring characteristics are discussed. 相似文献
17.
姿态传感器在水深测量中的应用 总被引：5，自引：5，他引：5
姿态传感器作为高精度动态海洋测量仪器，已被广泛地与船载海洋测量设备配套使用。姿态传感器能够改正或消除船载仪器由于船体的垂荡、横摇和纵摇引起的测量误差，大大提高测量精度。举例介绍了姿态传感器在单波束和多波束水深测量中的应用，并对姿态传感器的动态补偿特性进行了探讨和分析。 相似文献
18.
《中国海洋工程》2017,(4)
We present a study of the nonlinear coupling internal resonance for the heave roll and pitch performance of a spar platform under the wave and vortex-induced loads when the ratio of the frequencies of heave, roll and pitch are approximately 2:1:1. In consideration of varying wet surface, the three DOFs nonlinear coupled equations are established for the spar platform under the effect of the first-order wave loads in the heave and pitch, and vortexinduced loads in the roll. By utilizing the method of multi-scales when the vortex-induced frequency is close to the natural roll frequency, the first-order perturbation solution is obtained analytically and further validated by the numerical integration. Sensitivity analysis is performed to understand the influence of the damping and the internal detuning parameter. Two cases with internal resonance are shown. The first case is that no saturation phenomenon exists under small vortex-induced loads. The first order perturbation solution illustrates that only the vortex-induced frequency motion in roll and the super-harmonic frequency motion in heave are excited. The second case is that the vortex-induced loads are large enough to excite the pitch and a saturation phenomenon in the heave mode follows.The results show that there is no steady response occurrence for some cases. For these cases chaos occurs and large amplitudes response can be induced by the vortex-induced excitation. 相似文献
19.
Internal Resonances for Heave, Roll and Pitch Modes of A Spar Platform Considering Wave and Vortex-Induced Loads in the Main Roll Resonance 总被引：1，自引：0，他引：1
We present a study of the nonlinear coupling internal resonance for the heave roll and pitch performance of a spar platform under the wave and vortex-induced loads when the ratio of the frequencies of heave, roll and pitch are approximately 2:1:1. In consideration of varying wet surface, the three DOFs nonlinear coupled equations are established for the spar platform under the effect of the first-order wave loads in the heave and pitch, and vortex-induced loads in the roll. By utilizing the method of multi-scales when the vortex-induced frequency is close to the natural roll frequency, the first-order perturbation solution is obtained analytically and further validated by the numerical integration. Sensitivity analysis is performed to understand the influence of the damping and the internal detuning parameter. Two cases with internal resonance are shown. The first case is that no saturation phenomenon exists under small vortex-induced loads. The first order perturbation solution illustrates that only the vortex-induced frequency motion in roll and the super-harmonic frequency motion in heave are excited. The second case is that the vortex-induced loads are large enough to excite the pitch and a saturation phenomenon in the heave mode follows. The results show that there is no steady response occurrence for some cases. For these cases chaos occurs and large amplitudes response can be induced by the vortex-induced excitation. 相似文献