本文提出了一个一般的立方体单元格式并将其应用到三维Stokes问题的混合有限元逼近,给出了各向异性插值误差估计,相容误差估计和LBB条件成立的验证,从而证明了其在不满足正则性和拟一致条件下的收敛性.另外我们还得到了其-个特殊收敛性质,即在解(u,p)∈(H^3(Ω))^3×H^2(Ω)时,相容误差阶为O(h^2max),比插值误差阶O(hmax)高一阶。
In this paper, an anisotropic cubic mixed finite element for the 3D Stokes problem is introduced. We prove the LBB condition and give the error estimates of anisotropic interpolation error and consistency error. Then the convergence without the regularity and quasi-uniform assumptions on the mesh is obtained. Furthermore, a special convergence property is obtained, i.e., when (u,p)∈(H^3(Ω))^3×H^2(Ω), the consistency error is 2 O(h^2 max), which is higher than the interpolation error.