复合坡度珊瑚礁地形上波浪破碎的试验研究

通过波浪水槽试验,研究了珊瑚礁地形上规则波的破碎特征,包括破碎类型、破碎波高、破碎位置以及破碎带宽度。试验在带礁缘的复合坡度断面下进行,测试了两种水位下系列波高和波周期相组合的工况。试验研究了波浪破碎类型的区分标准,评估了已有四类破碎指标在复合坡度珊瑚礁地形上的适用性,并给出了描述破碎位置和破碎带宽度的经验公式。结果表明:礁边水深深水波高比可较好地区分波浪的破碎类型;四类破碎指标关系式中以破碎波高深水波高比之于深水波陡的相关性为最优;深水波高和礁边水深是影响破碎位置和破碎带宽度的主要因素,随着深水波高礁边水深比的增大,量纲一破碎位置（破碎点与礁边的距离和礁边处浅水波长的比值）逐渐减小,量纲一破碎带宽度（破碎带宽度和礁边浅水波长的比值）逐渐增大。     

Three Dimensional Baroclinic Numerical Model for Simulating Fresh and Salt Water Mixing in the Yangtze Estuary

For simulating fresh and salt water mixing in estuaries, a three dimensional nonlinear baroclinic numerical model is developed, in which the gradients of horizontal pressure contain the gradient of barotropic pressure arising from the gradi-ent of tidal level and the gradient of baroclinic pressure due to the gradient of salinity. The Eulerian-Lagrangian method is employed to descretize both the momentum equations of tidal motion and the equation of salt water diffusion so as to im-prove the computational stability and accuracy. The methods to provide the boundary conditions and the initial conditions are proposed, and the criterion for computational stability of the salinity fields is presented. The present model is used for modeling fresh and salt water mixing in the Yangtze Estuary. Computations show that the salinity distribution has the characteristics of partial mixing pattern, and that the present model is suitable for simulalion of fresh and salt waler mixing in ihe Yanglze Esluary.     

南黄海辐射沙洲形成发育水动力机制研究——Ⅰ.潮流运动平面特征

基于多站潮位及潮流多日连续观测资料 ,应用二维潮流数学模型对南黄海辐射沙洲海域潮流运动进行了大、中、小潮长时间序列连续数值模拟 .并从潮流沙脊发育的动力条件出发 ,对辐射沙洲海域的潮波传播过程、潮波能流率分布、潮差平面分布、多日平均潮流流速 ,潮流椭圆及水质点迹线图进行多目标分析和研究 .数值模拟结果表明 ,潮流是形成发育南黄海辐射沙洲的主要动力因素 ,潮能率、潮流流速分布的不同决定了辐射沙洲南北沙脊、深槽的空间分布与形态