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41.
在我国港口工程技术规范的波浪成长理论基础上,考虑到台风波浪的基本特点、等效水深的概念、浅水区波浪的折射、不规则波的能量分布特性、受陆岸和岛屿影响角度范围内的有效能量风区长度等因素,提出了受陆岸、岛屿影响浅水区(包括海湾区)台风风浪的计算方案。本方案只需台风中心位置、中心气压和计算点于各方位的风区长度(受陆岸影响部分)等资料,便可快速地得到计算点的波浪要素。经实测资料验证,效果良好。  相似文献   
42.
以松辽盆地地质资料为基础,介绍了应力场和张裂缝预测的计算方法。通过了各种岩性的张破裂概率隶属函数,预测松辽盆地酉部张裂缝区的分布。据此,为今后的油气勘探提出了几点认识和建议。  相似文献   
43.
- The variation of the amplitude of waves with varying incident angles when waves propagate through a typical approach channel is discussed by a numerical calculation method, the result of which shows that the influence of the channel on wave propagation is obvious. When the wave propagation direction is in coincidence with the channel axis, the wave amplitude ratio will decrease with the increase of propagation distance. When the incident angle is 15 - 30 , there appears an area of larger wave amplitude ratio on the side slope facing the waves, but at the another side, the wave amplitude ratio is generally small, indicating that the channel has a shielding effect. When waves propagate across the channel perpendicularly, the wave amplitude ratio can be calculated with the shallow water coefficient.  相似文献   
44.
通过分析近几年青岛市地表,地下水水质监测资料,总结水环境污染地区分布规律,摸清水环境污染形成原因,对当前防污治污工作提出了对策建议。  相似文献   
45.
Frequency-selective attenuation of sound propagaion and reverberation in shallow waterTXFrequency-selectiveattenuationofsoundp...  相似文献   
46.
波浪作用下海床的有效应力分析   总被引:4,自引:0,他引:4  
波浪作用下海床的稳定性分析是海洋工程地质评价的重要内容。海床的稳定性可通过计算分析其随时间变化的有效应力场来评估。本文建议了一个周期荷载作用下土体的本构模型 ,并用于计算波浪作用下海床的应力与变形。采用Biot固结理论和有限单元法 ,分析了海床的动态应力场与孔隙水压力场。波浪作用下两种渗透系数时有效应力的动态变化过程结果对比 ,反映了渗透消散作用对海床有效应力变化的影响  相似文献   
47.
Modest observations and numerical experiments were conducted to investigate circulation and brackish water dispersal in a coastal lagoon southwest of Taiwan. The Chi-Ku Lagoon, partially shielded from the sea by a string of sandbar barriers with two entrances among them, receives modest and episodic runoff from Chi-Ku Stream. Flood and ebb tidal streams entering and leaving the two entrances are found to converge and diverge in a flow stagnation area inside the lagoon. Under weak wind conditions, brackish water is preferentially retained in the flow stagnation area. Besides the observations, scenario runs using a three-dimensional numerical model also indicate strong modulation by monsoon winds. Both summer southwest monsoon and winter northeast monsoon reduce brackish water retention; the latter is found to be more effective. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
48.
Salt-water inflows into the Baltic Sea are important events for renewing the deep and bottom waters of the deep basins of the Baltic Sea. These events occur only at irregular intervals. The last strong event was in January 1993 followed by minor inflows in winter 1993/1994. As a result of these inflows, the deep water of the central Baltic basins was completely renewed.Based on extensive observations of polycyclic aromatic hydrocarbons (PAHs) in water, fluffy layer material and surface sediments between 1992 and 1998, the transformation of PAHs and the modification of their distribution in the Baltic deep water is discussed in connection with the spreading of the inflowing highly saline and oxygen-rich water along its pathway from the sills into the central basins. In the course of the inflows in 1993/1994, the PAH concentration in the deep water of the different basins increased significantly. The concentrations were elevated, at least by a factor of 2 and as much as seven to eight times (for the four-ring PAHs) compared to the previous and the following years. Two hypotheses for the causes were discussed: the inflowing salt water may have entrained more highly polluted surface water in the western Baltic Sea, or it may have entrained contaminated fluffy layer material or sediment particles along the route of transport.  相似文献   
49.
50.
The sway, heave and roll added masses of three uniform cylinders with semi-circular, rectangular and triangular cross-sectional shapes in shallow and narrow water are numerically analysed. The method is based on simulation of the potential flow induced by the cylinder's mode of motion. The effects of shallow and narrow water on added mass are analysed and presented. It is concluded that the shallow and narrow water effects on added mass depend on the different cross-section shapes of the cylinders. In particular, the water depth effect on sway added mass is stronger than that on heave added mass while the narrow water effect on sway is weaker than that on heave. The shallow water effect on added mass tends to weaken the narrow water effect. Lastly the effect of shallow and narrow water on added mass on a rectangular cylinder is the strongest while that on a triangular cylinder is the weakest.  相似文献   
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