退化两相Stefan动边界控制及其在非饱和土入渗中应用

结合孔隙水和孔隙气体在气液交界面上的力学条件,给出了一个退化的两相Stefan问题的最优控制模型;以交界面上的动边界为控制变量,描述了非饱和土中孔隙水的入渗和孔隙气体的排出过程,为水流入渗问题的求解提供了一种新的方法.数值结果表明,对导气率不同的土类,孔隙气体的排出过程对孔隙水入渗运动有不同的影响,对导气率低的土类影响很大,且不可忽略.

Degenerate two-phase Stefan moving boundary control and its application of water infiltration in unsaturated soil

A new optimal control model for degenerate two-phase Stefan problem is proposed and the boundary conditions of the problem belong to the mixed type. At the same time the model is used in the research of the pressured pore water infiltration and pore gas flow in unsaturated soil. The control equations with coupled boundary conditions on the interface are established based on the equilibrium analysis for pore water and pore gas separately, which can provide a new method to solve the problem of water infiltration. The numerical simulation of the water infiltration in dry sands and fly ash in two-dimensional shows that the influences of pore gas flowing on the water infiltration process are different for soil with different air permeability, which can not be ignored when air permeability of soil is low.