河道中可溶有机物迁移的分数阶导数力学本构模型研究

Dissolved organic matters are observed extensively in water environments and play a major role in pollutant migration. The mechanics model of dissolved organic matter migration is highly important in the water environment research. Because of diverse complex biological, physical, chemical processes, the classical convection-diffusion equation model and the traditional empirical formulas are incapable to describe such complicated migration. In particular, the power law heavy tail phenomena of dissolved organic matter migration are clearly observed in riverways through rough terrain. In recent years, my team has done a series of field tests at outdoor natural waterways and obtained a large amount of data, which is good preparatory work for this proposed research. This proposal plans to establish mechanics constitutive model via non-local fractional derivative approach to describe the migration of dissolved organic matter in riverways and to interpret power law heavy tail phenomena observed in field experiments. This project will make further field tests concerning organic content, water body temperature, and PH value in complex waterway to verify the applicability of the proposed model and to analyze the physics significance of model parameters. The goal of this study is to establish the effective mechanics model for dissolved organic matter migration using fewer parameters with clear mechanism to describe and predict such complicated migration process.

可溶有机物广泛存在于水环境中，是许多污染物的主要迁移载体，其迁移过程的力学模型是水环境研究中的一个重要问题。由于涉及到繁多且复杂的生物、物理、化学作用，经典的对流扩散方程模型和传统的经验公式难以精确地刻画这类复杂的迁移行为。尤其是在一些地形复杂的河道中，可溶有机物的迁移过程呈现明显的幂律拖尾现象，有关的研究还很不成熟。近年来本项目组在野外天然河道进行了一系列实验测量，获得了大量数据，为本项研究做了较好的准备工作。本项目拟采用非局部分数阶导数方法建立力学本构模型，描述可溶有机物在河道中的迁移机理，解释试验中观察到的幂律拖尾现象；并将进一步实验检测复杂河道中有机物含量、水体温度和PH值等实测数据；并用于验证模型的适用性，分析模型参数的实际物理意义。本项目研究的目标是建立河道中可溶有机物迁移的机理明确且参数较少的有效力学模型，以模拟和预测这类复杂的迁移过程。