规则波和不规则波作用下消波建筑物前的波高分析   总被引：1，自引：0，他引：1  

李荣庆  谢世楞 《海洋工程》1994,(1)

消波建筑物在国内外已得到广泛应用。本文采用近似方法分析了明基床上直立式消波建筑物前的波高及消波室内的波高，从而确定建筑物的消波效果。并在规则波的基础上将成果推广至不规则波作用下的情况。  相似文献   

白沙河地下水资源管理模型     

刘贯群  邱汉学  焦超颖 《中国海洋大学学报(自然科学版)》1994,(Z3)

针对白沙河地下水含水层的内部结构和本区开采特点以及已出现的环境问题，建立了地下水资源管理模型，确定了优化开采方案。该管理模型针对本区每年２个管理时段的长度及其开采量均不同的特点，导出了新的响应矩阵的公式。管理模型的建立有助于对该区地下水的合理开采。  相似文献   

滦河三角洲砂坝-潟湖海岸环境的遥感分析与区域开发潜力的评价     

刘宝银 《海洋科学进展》1992,(1)

本文就不同类型淀湖在不同时相条件下,对卫星遥感谱段响应的分析结果,将研究区的信息进行了提取与复合.继之,解译了封闭与半封闭漏湖的发育进程和表观特征,并就七个潟湖区段环境乃至开发前景作了详细的阐述.  相似文献   

Effect of wave-directionality on second-order loads induced by the set-down     

B. Molin  V. Fauveau 《Applied Ocean Research》1984,6(2):66-72

At first-order of approximation a sea-state may be considered as an infinite sum of Airy components with angular frequencies ω_i and wave-number vectors k_i. A second-order analysis shows the co-existence of long waves appearing at the difference frequencies ω_i—ω_j with wave-number vectors k_i—k_j. In shallow water they become appreciable in amplitudes and may induce slow-drift motion of moored structures.For small values of ω_i—ω_j,k_i—k_j may take all kinds of directions for an angular-spread wave system. Then it may be questioned how the in-line and transverse second-order accelerations compare to those obtained for a mono-directional wave-system.This analysis is carried out here by relating the spectra of the second-order horizontal accelerations to the directional wave-spectrum. Numerical applications are first performed for deep water. They show that at low frequencies, even for very narrowly spread wave systems, the transverse component is larger than the in-line component. In shallow water both components are dratically reduced as compared to the mono-directional case. As a consequence one may question the validity of model-testings or numerical models which take no account of the directionality of the wave-system.  相似文献   

Scattering of Semidiurnal Internal Kelvin Wave at Step Bottom Topography     

Yuji?KawamuraEmail author  Yujiro?Kitade  Masaji?Matsuyama 《Journal of Oceanography》2005,61(1):59-68

A three-dimensional, multi-level model was used to study the energy dissipation of semidiurnal internal Kelvin waves due to their interaction with bottom topography. A simplified topography consisting of a channel with an additional shallow bay was used to clarify the wave’s scattering process. When the first mode semidiurnal internal wave given at an open boundary arrives at the bay mouth, higher-mode internal waves are generated at a step bottom of the bay mouth. As a result, the energy of the first mode internal Kelvin wave is effectively decayed. The decay rate of the internal Kelvin wave depends on both the width and length of the additional bay. The maximum decay rate was found when a resonance condition occurs the bay, that is, the bay length is equal to a quarter of wave length of the first mode internal wave on the shallow region. The decay rate in the wide bay cases is higher than that in a narrow case, due to a contribution from the scattering due to the Poincare wave that emanates from the corners of the bay head. The decay rate with the additional bay is 1.1–1.8 times that of the case without the additional bay. The decay rate due to the scattering process is found to be of the same order as that of the internal and bottom friction.  相似文献   

On the recovery of surface wave by pressure transfer function     

Cheng-Han Tsai  Min-Chih Huang  Fu-Ji Young  Yin-Chern Lin  Hsien-Wen Li 《Ocean Engineering》2005,32(10):4936-1259

Except the commonly selected pressure transfer function derived from the linear wave theory, a previous study on the pressure transfer function for recovering surface wave from underwater pressure transducer suggested that the pressure transfer function is a function of frequency parameter only. With careful analysis, this study showed that the pressure transfer function should include a transducer submergence parameter as that given by the linear theory. It was found that the previously suggested empirical formula should be restricted to measurements with the pressure transducer close to the surface; otherwise overestimation of wave height would result. Field measurements were carried out with an acoustic wave gauge and a synchronized pressure transducer located at various depths with submergence parameter close to 1 (near the sea floor). It was shown that the previous one-parameter empirical formula might overestimate the significant wave height by more than 30%. This study found that with deep-water wave bursts excluded, the transfer function based on the linear wave theory provided a fairly good estimation on the significant wave heights, with an average deviation of 3.6%.  相似文献   

Fuzzy Fatigue Reliability Analysis of Offshore Platforms in Ice-Infested Waters   总被引：3，自引：3，他引：3  

方华灿  段梦兰  贾星兰  谢彬 《中国海洋工程》2003,17(3)

1 .IntroductionTheBohaiGulfisinfestedbyiceinthewholewinter,andoffshorestructuresthereexperiencenotonlywind ,waves ,currentsandearthquake ,butalsoiceloadswhicharecomplicatedbecauseofthedynamicinteractionbetweenicesheetsandstructures.Duanetal.( 2 0 0 0 )hadacomprehensivere viewofthelatestadvancesonice inducedvibration ,fatigueandfractureofoffshorestructures ,payingmuchattentiontothedifferencesinicebreakingmodeanddynamicsofstructuresindifferentice in festedwaters .Theypresentedcriticallythelates…  相似文献   

Wave-Current Forces on Vertical Cylinders in Side-by-Side Arrangement for Irregular Waves Combined With Opposing Current     

Li Yucheng Wang Fenglong Professor  Dalian University of Technology  Dalian Senior Engineer  Dalian University of Technology  Dalian 《中国海洋工程》1993,(1)

- The wave-current forces on vertical piles in side-by-side arrangement induced by irregular waves with opposing current are investigated experimentally in this paper. The characteristics in both time and frequency domain of in-line, lift and resultant forces are analyzed. The grouping effect coefficients of inline, lift and resultant forces on piles related to KC number and relative spacing parameters are given. These results are compared with those in the case of irregular waves combined with following currents. It is found that the results in these two cases are quite different. The range of KC number tested is 10- 60, the range of Reynolds number is (0.55-3.43) ×104.  相似文献   

The Nonlinear Wave Force on a Circular Cylinder in Shallow Water     

Qiu Dahong 《中国海洋工程》1992,(2)

Based on the 1st order cnoidal wave theory, the nonlinear wave diffraction around a circular cylinder in shallow water is studied in this paper. The equation of the wave surface around the cylinder is formulated and by using this formula the wave surface elevation on the cylinder surface can be obtained. In this paper, the formula for calculating the cnoidal wave force on a circular cylinder is also derived. For the wave conditions which are often encountered in practical engineering designs, the ratios of the nonlinear wave forces to the linear wave forces are calculated, and the results are plotted in this paper for design purposes. In order to verify the theoretical results, model tests are conducted. After comparing the test results with the theoretical ones, it is concluded that, in shallow water, for the case of T g / d~(1/2) > 8-10 and H / d > 0.3, the cnoidal wave theory should be used to calculate the wave action on a cylindrical pier.  相似文献   

Experimental study of reflection coefficient and wave forces acting on perforated caisson     

Chen Xuefeng  Li Yucheng  Sun Dapeng  Chen Renyou 《海洋学报(英文版)》2002,21(3):451-460

The reflection coefficient and the total horizontal forces of regular waves acting on theperforated caisson are experimentally investigated. The empirical relationship between reflection coefficient and the ratio of the total horizontal forces acting on the perforated caisson to those on solid vertical walls with the relative chamber width, relative water depth and porosity of perforated wall, etc. are given. Moreover, the results of the ratio of the total horizontal forces are also compared with formulas given by Chinese Harbour Design Criteria and Takahashi, which may be useful for the practical engineering application.  相似文献