刘小丽, 刘明珠. 波浪作用下考虑海床变形影响的溶质运移数值模拟[J]. 水科学进展, 2021, 32(1): 88-96. DOI: 10.14042/j.cnki.32.1309.2021.01.009
引用本文: 刘小丽, 刘明珠. 波浪作用下考虑海床变形影响的溶质运移数值模拟[J]. 水科学进展, 2021, 32(1): 88-96. DOI: 10.14042/j.cnki.32.1309.2021.01.009
LIU Xiaoli, LIU Mingzhu. Numerical simulation of the wave-driven solute transport in deformable seabed[J]. Advances in Water Science, 2021, 32(1): 88-96. DOI: 10.14042/j.cnki.32.1309.2021.01.009
Citation: LIU Xiaoli, LIU Mingzhu. Numerical simulation of the wave-driven solute transport in deformable seabed[J]. Advances in Water Science, 2021, 32(1): 88-96. DOI: 10.14042/j.cnki.32.1309.2021.01.009

波浪作用下考虑海床变形影响的溶质运移数值模拟

Numerical simulation of the wave-driven solute transport in deformable seabed

  • 摘要: 波浪会促进海水中溶质向海底沉积物运移,但已有研究大多未考虑海床(海底沉积物)变形效应的影响。为揭示波浪作用下海床土变形对溶质运移过程的影响机制,构建了考虑海床土变形影响的溶质运移计算模型,对波浪作用下溶质向砂质海底沉积物中的运移过程进行模拟。结果表明:海床土变形会增大孔隙水流速,进而增大溶质纵向水动力弥散系数,增强溶质运移的机械弥散作用,促进溶质向沉积物中运移;考虑海床变形时的溶质最大纵向水动力弥散系数可达不考虑海床变形时的8.5倍,约为分子扩散系数的545倍;海床土剪切模量越小,土体变形效应越明显,对溶质运移过程的影响越大;海床土饱和度的降低,会进一步加速波浪作用下溶质向海底沉积物的运移过程。

     

    Abstract: The process of solute transport into marine sediments from overlying water can be accelerated by waves. However, the effect of wave-induced deformation of seabed on solute transport has been ignored in most investigations. In response this paper investigates the influence of sandy bed deformation on the mechanism of solute transport using a modified solution-transport numerical model, in which the process of solute transport into deformable marine sediments from overlying water could be simulated under progressive waves. The results have shown that the seabed deformation will increase the velocity of pore water, which in turn increases the vertical hydrodynamic dispersion coefficient and the mechanical dispersion of solute transport. Therefore, the wave-induced deformation of soil will advance the process of solute migration into marine sediments. Case studies have indicated that in deformable soil the maximum vertical hydrodynamic dispersion coefficient could be 8.5 times that ignoring soil deformation, and about 545 times the molecular diffusion coefficient. The smaller the shear modulus of seabed soil, the more obvious soil deformation occurs, and the greater the influence of soil deformation has on solute transport. Furthermore, the reduction of degree of saturation will advance the solute transport into marine sediments.

     

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