【摘要】 为进一步探讨径流和潮汐两大重要动力因子对盐水入侵距离的影响机制,着重分析潮汐强度改变对盐水入侵发展的影响规律和主导过程,该文参考珠江磨刀门河道建立概化河道模型,设置不同驱动条件进行了一系列稳态数值试验。研究结果显示,径流和潮汐对盐水入侵的影响是一个共同作用的动态过程,潮汐增强对盐水运动最直接的影响在于促进盐分垂向输运,而径流对盐水的抬升和上溯起一定抑制作用,潮汐和径流的共同作用影响盐水纵向密度梯度,进而影响盐水入侵过程。因此,在不同流量范围,伴随着潮汐强度的改变,盐水入侵呈现出不同的表现规律。试验条件下,当径流小于3800m3/s且潮差小于2.0m时,盐水入侵距离基本随潮差增加而呈减小趋势。更多还原

【Abstract】 In order to explore the insight of dynamic influence of tide and runoff on estuarine salt intrusion, and focus on the internal dominant processes of intrusion development by the tidal strength, a series of numerical simulations for a simplified riverine estuary referring to the Modaomen waterway of Pearl River are carried out in this paper with distinct driving conditions at boundaries. The effects of runoff and tide on saltwater intrusion are co-operational and dynamical. The most direct actions of tides on salt flow lie in the promotion of mixing and vertical salt transport in addition to the flood-ebb convections while the runoff fresh flow restrains the uplifting and upstream of salt water. The sustainable runoff-tide cooperation affect the longitudinal density gradient which is important to the developments of salt intrusion. Hence, in different runoff stages, the intrusion lengths have different performances varying with different tidal strengths. Under the experimental conditions, the intrusion lengths generally decrease with increasing tidal ranges if the runoff are less than 3800 m3/s and tidal ranges less than 2.0 m.更多还原