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1.
若海洋离岸工程结构物浮力小时,可借助于浮筒来实现拖航。在波浪载荷下研究结构物和浮筒之间的相互作用力,是有实际意义的.本文是以海上石油开采导管架的拖航为例,进行了模型拖航试验。给出了结构物和浮筒之间相互作用力的测试方法和设备,利用船模试验池(简称船池)的规则波,求出在定航速下波浪参数和相互作用力之间的关系曲线.最后,本文对试验结果进行了讨论。 相似文献
2.
介绍了一种新型的Spar平台。由于Spar平台属柔性连接结构,允许其在一定范围内运动,故二阶漂移力为系统稳定性的控制荷载,而线形波浪力则可导致系泊系统产生疲劳破坏。为此,文中结合分析此新型平台所受水动力特性,比较其相对于现有Spar平台的优势。由于浮筒位于水下一定深度处,新型平台所受线性波浪力和二阶波浪力均大幅度减小,尤其是后者可减至现有Spar平台受力的2%左右,所以大大地改善了平台的稳定性和系泊系统的抗疲劳破坏能力。由于在上部平台和浮筒之间增加了导管架,使得各模块间的连接点大大减小,从而又方便了海上施工作业。 相似文献
3.
多锚链系泊浮筒非线性漂移运动的时域模拟 总被引：3，自引：0，他引：3
本文对多锚链系泊浮筒漂移运动的非线性效应进行了讨论。在波浪力和锚链系泊力都是非线性的条件下,对浮筒的运动作时域模拟,并把计算单个系泊锚链流体动力作用的Koterayama W.方法推广到多系泊锚链的情形。计算了规则波和波群中系泊浮筒漂移运动的时间历程,讨论了其运动与波高、频差的关系。可以指出,系泊浮筒系统总漂移运动受锚链流体动力的影响很大;在波群中,其幅值主要受波高支配,与频差的关系较小。 相似文献
4.
针对双浮筒直驱式波浪发电系统的工作效率较低问题,提出了一种基于PID(Proportional Integral Derivative)控制的系统优化方法。首先根据波浪力学理论,计算出了双浮筒直驱式波浪发电系统的外浮筒(动浮筒)在自然条件下的运行特性,计算结果表明,受到波浪频率、垂直波浪速度和波浪周期固有特性的影响,外浮筒的垂直运动速度不能与波浪的垂直运动速度达到共振,进而也就导致波浪能转换成电能的工作效率较低。当采用基于PID控制算法对该波浪发电系统进行优化控制之后,波浪能转换成电能的效率有了很大的提高。详尽的算例分析和仿真结果表明本文提出的优化控制方法有效、可行。 相似文献
5.
第一个刚臂式单点系泊储油装置(SBS)于1974年在突尼斯建成,以后在各地又建成了很多个这类装置,据报导其使用效果是令人满意的[1,2].为了发展我国海洋石油勘探、开发的科学技术,在海洋石油研究所的协助下,我们对这种系泊系统进行了波浪模型试验研究,本文在试验成果的基础上,主要研究单点浮筒多链系统的静力特性和波浪要素、水深等对链力的影响,还研究了减小中链力的措施. 相似文献
6.
超大型浮式结构物是一种新型海上结构,浮体结构的不同构型对水动力性能有着较大的影响,而合理可靠地预报波浪载荷是保证海洋结构物设计合理和安全运营的基本前提。基于设计波法,采用莫里森公式和势流理论相结合的方法,对纵向浮筒和横向浮筒两种不同构型的超大型浮式结构物进行水动力分析和波浪载荷长期预报并进行对比分析。研究结果表明:横向浮筒超大型浮体纵荡运动相应幅值比纵向浮筒超大型浮体小很多;纵向扭转为纵向浮筒和横向浮筒超大型浮体最危险工况,其次是垂向弯矩工况;且横向浮筒超大型浮体的垂向弯矩也是较危险的工况。分析结果可为超大型海上浮式结构物的结构设计提供相关合理可靠的理论依据。 相似文献
7.
8.
浅水域生存工况下系泊浮筒系统三维运动 总被引：1，自引：0，他引：1
本文提出一个浅水域生存工况下，多锚链系泊浮筒系统三维运动的工程计算模型，对链系采用射的法计算，使其与浮筒运动计算相匹配。对不同的风波流方向及链刚度，计算了浮筒的运动及链力，结果显示本文的模型是合理的。 相似文献
9.
直立式防波堤堤头在斜向波浪作用下波浪力的计算在现行的技术规范中尚属空白。通过物理模型试验给出了堤头结构设计所需的波压分布图，指出了波浪入射方向和地形对堤头所受波浪力的贡献有时可以超过波高和波周期，根据现行规范按波浪正向入射计算堤头所受的波浪力偏于安全。 相似文献
10.
圆柱形沉浮式深海养殖网箱的受力分析 总被引：9，自引：0，他引：9
应用一系列力学关系，研究了深海圆柱形沉浮式养殖网箱所承受的波浪力情况。导出深海沉浮式养殖网箱的运动方程，并给出数值计算。在网箱波浪力的研究中采用绕射理论和Morison方程，讨论了在波高、波长及周期变化下水动力的变化趋势，得出网箱所受到的水平波浪力远大于竖直波浪力，波高的变化对波浪力的影响最大的结论，为深海网箱的设计校核提供1种参考方法。 相似文献
11.
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12.
An experimental study has been carried out on the forces from plunging breaking regular and irregular waves on a vertical cylinder on a shoal. Total as well as local wave forces have been measured. Engineering formulae for the calculation of the horizontal forces and overturning moments have been derived. The duration of the impact forces have been measured and compares fairly well with theoretical values. 相似文献
13.
In the past few decades, considerable efforts have been devoted to the phenomenon of wave-seabed interaction. However, conventional investigations for determining wave characteristics have been focused on the wave nonlinearity. On the other hand, most previous works have been only concerned with the seabed response under the wave pressure, which was obtained from the assumption of a rigid seabed. In this paper, the inertia forces and employing a complex wave number are considered in the whole problem. Based on Biot’s poro-elastic theory, the problem of wave-seabed interaction is first treated analytically for a homogeneous bed of finite thickness and a new wave dispersion relationship is also obtained, in which the soil characteristics are included. The numerical results indicate that the effects of soil parameters significantly affect the wave characteristics (such as the damping of water wave, wave length and wave pressure). Furthermore, the effects of inertia forces on the wave-induced seabed response cannot always be ignored under certain combination of wave and soil conditions. 相似文献
14.
1 IntroductionRecently breakwaters with perforated front wallshave been widely used. The use of perforated break-waters mainly has two advantages. Firstly, wave forcesacting on the whole structure can be divided into twoparts on two different walls with a phase difference.To select the distance between the two plates suitably,the total wave force on the whole structure can bemaintained at a low level. Secondly, waves will dissi-pate when they transmit over a porous medium. Thus,the reflection… 相似文献
15.
A new technique for measuring velocities under breaking wave crests using laser-doppler anemometry has been developed. Results may be obtained at positions up to 4 millimeters from the crest.A wave field is presented for a vertically fronted wave and comparison is made with an appropriate numerical study. The velocities obtained are far in excess of the predictions of linear theory.Measurements have also been made of the forces produced by this wave on a horizontal cylinder. Comparisons with large regular waves indicate that forces due to breaking waves can be up to five times greater for similar wave heights. 相似文献
16.
1 .IntroductionTraditionally ,thedesignofcoastalstructuresisbasedontheformulaedevelopedforhead onuni directionalwaves .However,wavesusuallyattackabreakwaterobliquely ,formingshort crestedwavesinfrontofthebreakwater.Ontheotherhand ,asthehumanactivityareaisspreading ,thewaterdepthattheconstructionsiteforbreakwatershasatendencytobecomelarge ,andsomebreakwatershavebeenconstructedinwaterareasdeeperthan 6 0minJapan (Tanimotoetal.,1 988) .Theseawaveismulti directionalandrandom ,especiallyindeepwater… 相似文献
17.
《Applied Ocean Research》2007,29(1-2):45-54
Catenary mooring lines are typically subjected to bimodal loads, comprising of a wave frequency (WF) component due to the first-order wave forces and a low frequency (LF) component induced by the second-order wave forces. For moored vessels, the LF forces due to current and wind also play a role. Only dynamic wave loads are considered herein, while current and wind loads are modeled as constant forces. Because of the nonlinearities of the mooring line characteristics, the dynamic line tension and the second-order responses, both the WF and LF line tensions are in principle nonGaussian. These facts make it difficult to estimate the combined fatigue damage of mooring lines in the frequency domain. A fatigue combination rule based on the Jiao and Moan’s theory has been extended to cover the nonGaussian case. The purpose of this paper is to improve and validate the frequency-domain method by time-domain analysis based on a simplified, but accurate mechanical model of the dynamic line tension. Improvements on the LF and combined fatigue damage estimation have been made by considering the nonsymmetrical property of the LF line tension distribution. Both the WF and LF mooring line tensions due to wave loading have been simulated in the time domain for different sea states and the combined fatigue damage has been estimated by using the rainflow cycle counting algorithm. The accuracy of the frequency-domain method for estimating the bimodal nonGaussian fatigue damage of mooring lines has been verified by the time-domain simulations and is considered to be acceptable. 相似文献
18.
This paper presents recent advances in knowledge on wave loads, based on experimental work carried out in the CIEM/LIM large flume at Barcelona within the framework of the VOWS (Violent Overtopping by Waves at Seawalls) project. Both quasi-static and impact wave forces from the new data set have been compared with predictions by empirical and analytical methods. The scatter in impact forces has been found to be large over the whole range of measurements, with no existing method giving especially good predictions. Based on general considerations, a simple and intuitive set of prediction formulae has been introduced for quasi-static and impact forces, and overturning moments, giving good agreement with the new measurements. New prediction formulae have been compared with previous measurements from physical model tests at small and large scale, giving satisfactory results over a relatively wide range of test conditions. The time variation of wave impacts is discussed, together with pressure distribution up the wall, which shows that within experimental limitations the measured pressures are within existing limits of previous study. 相似文献
19.
Numerical investigation on the dynamics of a vertical wall defenced by an offshore breakwater 总被引：1，自引：0，他引：1
The numerical and experimental investigations on the performance of an offshore-submerged breakwater in reducing the wave forces and wave run-up on vertical wall are presented. A two-dimensional finite-element model is employed to study the hydrodynamic performance of the submerged breakwater under the action of regular and random waves. The numerical prediction has been supported with experimental measurements. The wave forces and wave run-up on the vertical wall were measured for different breakwater configurations. The applicability of linear theoretical model in the prediction of wave forces on the wall by a submerged breakwater has been discussed. 相似文献
20.
Forces and moment on a horizontal plate due to wave scattering 总被引：1，自引：0，他引：1
Mana Patarapanich 《Coastal Engineering》1984,8(3):279-301
Wave reflection and transmission from a fixed horizontal plate have been widely studied but theoretical solutions are only available for certain limiting conditions. A general solution for this wave scattering problem is presented using the finite-element method, covering the whole range of relative depth ratio from shallow to deep water limits and submergence depth ratio from the water surface to the bed. Existing long-wave solutions for the surface plate and the submerged plate have been extended to obtain the hydrodynamic forces and overturning moment exerted on the plate. Results from the finite-element program compare well with these solutions. Variations of the reflection coefficient, wave forces and moment, with the plate width to wave length ratio, relative depth ratio and submergence depth ratio are discussed. 相似文献