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41.
-Nonlinear tidal waves in a kind of estuary are studied in the paper using one-dimensional nonlinear hydrody-namic equations with friction. The estuary has exponentially varying width B=B0 e-bx and uniform depth h. The one-dimensional hydrodynamic equations are solved by perturbation method. It was found that our solution included two special cases, Pelisenpeki's solution and Airy's solution. The former can be got by letting b=0 in our solutions, and the latter by setting 6 = 0 and f= 0 (f is linear frictional coefficient). In terms of the second-order solution, the physical mechanism of nonlinear tidal waves in estuaries with gradually varying cross-section is explored. It is shown that, under the assumption of linear friction coefficient, shallow water constituent waves consist of two parts, one is produced by shallow water nonlinear effect outside the estuary, the other is generated by shallow water nonlinear effect inside estuary. In addition, the physical mechanism of the residual tidal current and 相似文献
42.
养殖对虾病毒性疾病的细菌并发症防治研究 总被引:1,自引:0,他引:1
本文研究报道了发病对虾肝胰腺分离菌物敏感性,采用防台细菌人工感染方法进行药物饲料的筛选,在实验室及养殖池中进行药物饲料的防治效果试验。结果表明,在对虾病毒流行期间,采用药物饲料可有效防止对虾爆发性大量死亡,提高对虾存活率。 相似文献
43.
Zhang Furan Zhao Jun Zhang Xueqin Assistant Researcher Tianjin Research Institute of Water Transport Engineering Tianjin Assistant Engineer Tianjin Research Institute of Water Transport Engineering Tianjin 《中国海洋工程》1993,(2)
In respect of an offshore berthing pillar, the test study result of current force acting on mooring ships is described in this paper. Empirical and semi-empirical relationships of current force coefficient are given according to the angle between the flow direction and the ship's longitudinal axis, which are coincident with the result of theoretical analysis. 相似文献
44.
A Computational Model for Velocity Separation in Shallow Sea 总被引:1,自引:0,他引:1
Based on the hydrodynamical feature and the theoretical velocity profiles of tidal flow and vvind-induced flow in shal-low sea, a computational model is established for the first time, which can separate observed velocity into tidal velocity and wind-induced velocity by use of the least square method. With the model, not only the surface velocities of tidal flow and vvind-induced flow are obtained, but also the bed roughness height is determined and the wind velocity above the wa-ter surface is estimated. For verification of the model, the observed velocity in the Yellow River Estuary and the laborato-ry test is separated, then it is applied to the Yangtze River Estuary. All the results are satisfactory. The research results show that the model is simple in method, feasible in process and reasonable in result. The model is a valid approach to analysis and computation of field dala, and can be applied to separate the observed velocity in shallow sea; at the same time, reasonable boundary conditions of th 相似文献
45.
46.
青海湖全新世植被演变及气候变迁:QH85—14C孔孢粉数值分析 总被引:20,自引:3,他引:20
本文应用青海湖QH85-14C孔取得的具有~(14)C测年数据所支持的原始孢粉资料,进行数值分析(有序聚类、主成份分析、滑动平均和回归分析)。从而对青海湖区11000年以来的植被和气候变化进一步讨论。 相似文献
47.
大沽河是胶州湾最大的入海河流,每年都会给胶州湾带来大量泥沙。本文利用三维的ECOMSED水动力-泥沙数值模型对洪水期的大沽河进行了数值模拟,得到了洪水存在期间以及洪水结束后胶州湾的余流分布、大沽河河道上中下游各层盐度、泥沙浓度随时间变化的趋势以及入海冲淡水和泥沙对胶州湾的影响。 相似文献
48.
A vertical two-dimensional turbulence numerical model for the interaction of waves and currents is developed in the paper based on the nonlinear two-equation k-ε model with the VOF method.The one-dimensional equivalent advection velocity and equivalent mixing coefficient are defined and the solving process is introduced:The pollutant concentration field,generated by an instant source in waves and currents,is calculated with the model,and then the equivalent advection velocity and equivalent mixing coefficient are obtained by calculating the time derivative of the mean and variance of pollutant concentration probability distribution.The effects of wave period and wave height on the equivalent mixing coefficient for waves and wave-currents are also investigated. 相似文献
49.
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