Interaction Between Waves and A Comb-Type Breakwater

The characteristics of wave transmission, reflection and energy dissipation of comb-type caisson breakwaters are studied through laboratory physical model tests. Regular and irregular waves, with a wide range of wave heights and periods and a constant water depth, are considered. Different dimensions of each portion of the comb-type caisson breakwater are tested. Empirical formulae for calculating the reduction coefficient k, which is the ratio of horizontal wave force on unit length of the comb-type breakwater to that on unit length of the vertical wall breakwater, and for calculating the reflection coefficient of waves k, are obtained from the measurements. The comb-type caisson breakwater has been found to be very efficient in dissipating incident wave energy and in reducing wave reflection, and has already been used for the construction of an island breakwater in the Dayao Bay of Dalian Port, Liaoning Province, China. Compared with the cost of a common caisson breakwater, about 24. 5% of the investm     

浅谈地质立项工作

就目前地质工作而言,以地质立项工作争取国家、地方财政资金是地勘单位主要工作之一。财政项目的多少不仅反映一个地勘单位的技术实力,同时也体现一个地勘单位的地勘经济规模。立项上作的成败与否,关键在于立项项目意义的明确性．立项依据的充分性,项目实施的可行性,项目成果的经济性,关键技术的突破性、创新性,项目成果的应用性和推广性等。     

Numerical Simulation of Hydrodynamic Behaviors of Gravity Cage in Waves

This paper aims at investigation of the dynamic properties of gravity cage exposed to waves by use of a numerical model. The numerical model is developed, based on lumped mass method to set up the equations of motion of the whole cage; meanwhile the solutions of equations are solved by the Runge-Kutta-Verner fifth-order and sixth-order method. Physical model tests have been carried out to examine the validity of the numerical model. The results by the numerical simulation agree well with the experimental data.     

海带早期成岩过程中形态和物质变化的实验室模拟

过实验室模拟海带的早期成岩作用过程,获得生物改造无定形体样品,观察海带形态变化,测定生化成分、碳氢 氮元素及微量重金属元素含量,为海相底栖宏观藻类的烃源岩形成过程提供现代对比实例。研究结果显示海带在模拟过程 中不断降解,到第 67 天海带细胞已经完全破碎呈无定形体状;微生物促进海带生化成分的转化,厌氧后期多糖和蛋白质含 量下降,粗脂肪含量上升到 8.16%;海带对微量重金属元素有显著的吸附解析作用,使微量元素含量波动变化。早期成岩 过程中微生物改造使海带形态朝无定体转化;有利于脂类成分的增加,利于成烃;元素变化有一定规律,但要直接利用微 量重金属元素进行油源对比可能还存在一些问题,需要进一步研究。     

开孔沉箱在斜向入射波作用下受力研究

应用透空壁内流体速度与壁两侧的压力差成正比的线性模型,研究了斜向波与无限多个开孔沉箱的相互作用.依照结构物的几何形状,把整个流域分成无限多个子域,在每个子域内应用特征函数展开法对速度势进行展开.对于沉箱内的波浪运动,引入相位差概念;在构造反射波模型时,考虑了结构物的几何形状影响.列举出物理模型实验结果与数值实验结果的比较,可以看出两者吻合较好.进一步的数值计算验证表明,当孔隙系数无限大时,开孔墙前后的速度非常接近.在低频入射波作用下,垂直于沉箱的水平力随角度的变大而减小,平行于沉箱排列方向的力则变大.     

Numerical Investigation of High Tide Level Due to A Super Typhoon in A Coastal Region

A numerical model of the coupling between astronomical tide and storm surge based on Mike 21 is applied to the coastal regions of Zhejiang Province.The model is used to simulate high tide levels combined with storm surge during 5 typhoons,including two super typhoons,that landed in the Province.In the model,the atmospheric forcing fields are calculated with parametric wind and pressure models.The computational results,with average computed errors of 13 cm for the high astronomical tide levels and 20 cm for the high storm-tide levels,show that the model yields good simulations.Typhoon No.5612,the most intense to land in China since 1949,is taken as the typical super typhoon for the design of 5 typhoon routes,each landing at a different location along the coast.The possible extreme storm-tide levels along the coast are calculated by the model under the conditions of the 5 designed typhoon routes when they coincide with the spring tide.Results are compared with the high storm-tide levels due to the increase of the central atmospheric pressure at the base of a typical super typhoon,the change of tidal type,and the behavior of a Saomai-type typhoon.The results have practical significance for forecasting and minimization of damage during super typhoons.     

从软体动物分布谈淮河及长江下游第四纪地层和古地理

淮河、长江下游广大地区地势平坦 ,河、湖、港发育 ,第四纪地层出露良好 ,可分为平原区、丘陵区二种类型。第四纪时 ,本地区气温适宜 ,雨量充足 ,河湖密布 ,沼泽宽阔 ,优越的生态环境适合软体动物生存和繁衍 ,因此软体动物属种数量繁多 ,分布广泛。在淮河及其两岸丽蚌 (L amprotula)、矛蚌 (L anceolaria)、曲蚌 (Arconaia)很昌盛 ,长江下游南岸金坛、宜兴蚬科 (Corbiculidae)化石堆积厚可达 1m以上。     

双色入射波下二阶波浪力响应函数

应用边界元方法,对双频入射波在和频及差频下的二阶速度势做了完整的求解,通过物面积分计算了任意三维结构上的二阶波浪力的传递函数.对简单几何物体,与发表的结果做了对比,两者吻合良好,验证了本方法的正确性.应用这一方法还对复杂的张力腿平台模型做了实际计算,发现在低频和高频区二阶波浪力平方响应函数有着显著的能量分布.     

基于波形不对称性的波浪破碎指标

为了探寻波浪破碎与波形不对称性的关系,通过对1/200缓坡上波浪破碎实验研究结果的进一步分析,运用最小二乘法,拟合了波形不对称性参数与相对水深的关系,以及用波形不对称性参数表示的波浪破碎指标表达式。所得规则波的结果与Kjeldsen的深水波结果相同,而不规则波的结果比规则波的小。研究还表明,这一破碎指标与相对水深有关系,随着水深变浅,指标值增大。     

A 3-D Numerical Model for the Calculation of Water Wave Transformation in Large Area

Based on the integral equation transformed from three dimensional Laplace equation and by the adoption of the division manner of sub- region boundary element method, the numerical computations of the velocity potential of each sub-region are given considering the continuity conditions of potential and normal derivatives at the interface of sub-regions. Therefore, computation of wave deformation in offshore flow field is realized. The present numerical model provides a good solution for the application of boundary element method to the calculation of wave deformation in large areas.