借助于类Wilson元对一类四阶抛物方程提出了一个非协调混合有限元向后欧拉全离散格式。利用该元的一个特殊性质,即精确解u∈H^3(Ω)/H^4(Ω)时,其非协调误差在能量模意义下可以达到O(h^2)/O(h^3)阶,再结合双线性元的高精度结果,采用分裂技巧,得到了原始变量u和中间变量q=Δu的H^1模意义下具有O(h^2+τ)阶的超逼近性质,其中,h和τ分别表示空间剖分参数和时间步长。
By means of the quasi-Wilson element, a fully-discrete nonconforming mixed element scheme is established for a kind of fourth-order parabolic equations in back ward Euler fully-discrete case. By using the special character of the element, that is, the consistency error can be estimated with O(hz)/O(h^3) in broken energy norm when u belongs to H^3 (Ω)/H^4 (Ω), the splitting technology and the high accuracy analysis of bilinear finite element, the superclose results with order O(h^2+r) of original variable u and interme- diate variable Δ= Au in H^1-norm are obtained. Here,h and r are parameters of subdivision in space and time step.