潮汐河段挖入式港池异重流淤积探讨  

A DISCUSSION ON THE DEPOSITION OF DENSITY FLOW IN THE DREDGED BASIN FOR THE REACH OF TIDEWAY

作　　者：严镜海 

机构地区：[1]南京水刊科学研究院

出　　处：《海洋工程》1991年第2期41-53,共13页The Ocean Engineering

摘　　要：盐水与泥沙异重流的基本运动特性是相类似的。文本利用盐水楔扩散问题试验研究的成果,应用到泥沙异重流受潮汐影响的扩散和淤积分析。利用紊动能量损失与扩散系数之间关系,进行潮汐河段异重流问题的研究;并求得紊动能量损失指标G/J<50,属异重流范围。又利用挖入式港地实际淤积资料与淤积计算对比分析,初步认识到异重流淤积量占总量相当大的比例,是由于落潮时无径流量而只有些潮蓄量下泄,流速很小而形成异重流。此外,小潮大径流量时,也有异重流。 在潮汐河段上,由于水位与流速随涨落潮的过程不断地改变,除涨落地期间流速较小外,一般流速较大,即使产生了盐水楔,它也不能持久。因此有人认为有潮汐的盲肠河段或挖入式港池内,不会有异重流的淤积问题。但另有一些人认为水流情况与有潮河段并不完全相同。如在落潮时只有盲肠或港池的潮蓄量外泄,流速很小,有利于形成异重流而淤积。因有上述二种不同看法,故对潮汐河段挖入式港池异重流淤积进行初步探讨。The fundamental characteristics of movement of density flow are similar with those of the saline wedge. The research results of the diffusion investigation of saline wedge are applied to the analysis of the diffusion and deposition of the density flow which is affected by tides. The relationship between the turbulent energy loss and the coefficient of diffusion is used to study the density flow in the reach of tideway, and the index of the turbulent energy loss G/J<50 which belongs to the density flow is found. From the comparison of the field deposition data in the dredged basin with the computational results, it is preliminarily acknowledged that the deposits of the densilty flow occupy a fair large proportion of total deposition. The main cause of density flow formed is the very small flow velocity from the tidal storage during ebbs. Besides, when the neap tide occurs with large run off, the density flow also occurs.

关 键 词：挖入式港池 紊动 盐水楔 淤积问题 潮汐作用 涨落潮 落潮时 淤积量 淤积计算 流速分布 

分 类 号：P75[天文地球—海洋科学]