研究了Sobolev方程的H~1-Galerkin混合有限元方法.利用不完全双二次元Q_2~-和一阶BDFM元,建立了一个新的混合元模式,通过Bramble-Hilbert引理,证明了单元对应的插值算子具有的高精度结果.进一步,对于半离散和向后欧拉全离散格式,分别导出了原始变量u在H~1-模和中间变量p在H(div)-模意义下的超逼近性质.
In this paper,H~1-Galerkin mixed finite element method for Sobolev equation is studied.A new mixed finite element pattern is constructed using incomplete biquadratic element Q_2~- and first order BDFM element.Through Bramble-Hilbert lemma,high precision results of interpolation operators corresponding to unit are proved.Further,the superclose properties for the primitive variables u in H~1-norm and the intermediate variable p in H(div)-norm are obtained respectively in semi-discrete and the backward Euler fully discrete schemes.