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针对众多高浊度河口泥沙粒径普遍较小、絮凝作用显著，而其对盐度层化与悬沙层化间非线性相互作用的影响机制尚未明确的现状，本研究建立了考虑絮凝过程的一维水柱数值模型，系统探讨絮凝对该相互作用的调节效应与内在机制。结果表明，絮凝未改变盐-沙层化耦合的基本反馈结构：稳定盐度层化倾向于增强悬沙层化，而不稳定盐度层化则起到削弱作用；稳定的悬沙层化则对盐度层化(无论其稳定性)均具有正反馈效应，该机制在黏性与非黏性泥沙条件下均表现一致。然而，絮凝通过加速泥沙沉降、降低悬沙浓度，削弱了悬沙层化强度，从而整体抑制盐-沙层化之间的非线性耦合，这一表现与非黏性情形存在显著差异。此外，絮凝的调节效应对纵向盐度梯度与潮流流速的变化呈现出不同的敏感程度。本研究揭示了泥沙絮凝在调节盐-沙非线性相互作用中扮演的关键角色，强调了在河口海岸数值模型中引入絮凝过程对于准确表征水动力结构与密度层化的重要性，并为理解高浊度河口水-盐-沙耦合运移格局提供了理论依据。
Abstract：In numerous highly turbid estuaries, suspended sediment is generally fine-grained and flocculation is prominent, yet the mechanism by which flocculation regulates the nonlinear interaction between salinity-induced stratification(SaIS) and sediment-induced stratification(SeIS) remain unclear. To address this gap, this study develops a one-dimensional water column numerical model that incorporates flocculation processes to systematically investigate its regulatory effects and underlying mechanisms. The results show that flocculation does not alter the fundamental feedback structure of salinity-sediment stratification coupling. The stable SaIS tends to enhance SeIS, whereas the unstable SaIS tends to suppress it. In contrast, stable SeIS exerts a positive feedback on SaIS, regardless of its stability. This mechanism is consistently observed under both cohesive and non-cohesive sediment conditions. However, flocculation weakens the intensity of SeIS by accelerating sediment settling and reducing suspended sediment concentration. As a result, the overall nonlinear coupling between SaIS and SeIS is suppressed, which exhibits a marked difference from the non-cohesive sediment case. Furthermore, the modulatory effects of flocculation exhibit varying degrees of sensitivity to changes in longitudinal salinity gradient and tidal current velocity. This study reveals the critical role of sediment flocculation in modulating the nonlinear interaction between salinity and sediment. It highlights the importance of incorporating flocculation process into estuarine and coastal numerical models to accurately represent hydrodynamic structures and density stratification. It provides theoretical support for understanding the pattern of current-salinity-sediment coupled transport in highly turbid estuaries.
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基本信息:
DOI：10.16441/j.cnki.hdxb.20250178
中图分类号:TV148.1
引用信息:
[1]周健,张文哲,陈聿奇.考虑絮凝调节的河口盐度层化与悬沙层化非线性相互作用研究[J].中国海洋大学学报(自然科学版),2025,55(12):126-137.DOI:10.16441/j.cnki.hdxb.20250178.
基金信息:
国家自然科学基金青年科学基金项目(52209085); 江苏省自然科学基金面上项目(BK20252048)资助~~
2025-05-27
2025
2025-06-25
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1
2025-11-24
2025-11-24