Numerical simulation of contaminant biodegradation by higher order methods and adaptive time stepping
Numerical simulation of contaminant biodegradation by higher order methods and adaptive time stepping
复制标题
通过高阶方法和自适应时间步长进行污染物生物降解的数值模拟
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
P. Knabner
中科院分区：
文献类型：
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作者：
M. Bause;P. Knabner
在这项工作中，我们提出并分析了一个可靠的和强大的近似方案，生化反应运输在地下Monod型动力学。水流由理查兹方程模拟。该方法空间离散采用高阶有限元法，时间离散采用两步向后微分法。由此产生的非线性代数方程组求解阻尼版本的牛顿法。对于Newton迭代的线性问题，使用Krylov空间方法。在现实的地下（地下水）污染的情况下进行的计算实验中，我们表明，高阶近似方案显着降低了固有的数值扩散量相比，低阶的。因此，避免了人为的横向混合的物种，导致一个强烈的高估的生物降解过程。最后，我们提出了一个强大的自适应时间步进技术的耦合流动和运输问题，允许有效的长期预测的生物降解过程。
In this work we present and analyze a reliable and robust approximation scheme for biochemically reacting transport in the subsurface following Monod type kinetics. Water flow is modeled by the Richards equation. The proposed scheme is based on higher order finite element methods for the spatial discretization and the two step backward differentiation formula for the temporal one. The resulting nonlinear algebraic systems of equations are solved by a damped version of Newton’s method. For the linear problems of the Newton iteration Krylov space methods are used. In computational experiments conducted for realistic subsurface (groundwater) contamination scenarios we show that the higher order approximation scheme significantly reduces the amount of inherent numerical diffusion compared to lower order ones. Thereby an artificial transverse mixing of the species leading to a strong overestimation of the biodegradation process is avoided. Finally, we present a robust adaptive time stepping technique for the coupled flow and transport problem which allows efficient long-term predictions of biodegradation processes.