A stabilizer free WG method is introduced for the Stokes equations with superconvergence on polytopal mesh in primary velocity-pressure formulation. Convergence rates two order higher than the optimal-order for velocity of the WG approximation is proved in both an energy norm and the $ L^2 $ norm. Optimal order error estimate for pressure in the $ L^2 $ norm is also established. The numerical examples cover low and high order approximations, and 2D and 3D cases.
Citation: Xiu Ye, Shangyou Zhang. A stabilizer free WG method for the Stokes equations with order two superconvergence on polytopal mesh[J]. Electronic Research Archive, 2021, 29(6): 3609-3627. doi: 10.3934/era.2021053
A stabilizer free WG method is introduced for the Stokes equations with superconvergence on polytopal mesh in primary velocity-pressure formulation. Convergence rates two order higher than the optimal-order for velocity of the WG approximation is proved in both an energy norm and the $ L^2 $ norm. Optimal order error estimate for pressure in the $ L^2 $ norm is also established. The numerical examples cover low and high order approximations, and 2D and 3D cases.
[1] | A note on the optimal degree of the weak gradient of the stabilizer free weak Galerkin finite element method. Appl. Numer. Math. (2020) 150: 444-451. |
[2] | The lowest-order stabilizer free weak Galerkin finite element method. Appl. Numer. Math. (2020) 157: 434-445. |
[3] | Superconvergence of numerical gradient for weak Galerkin finite element methods on nonuniform Cartesian partitions in three dimensions. Comput. Math. Appl. (2019) 78: 905-928. |
[4] | Superconvergence of the gradient approximation for weak Galerkin finite element methods on rectangular partitions. Appl. Numer. Math. (2020) 150: 396-417. |
[5] | New error estimates of nonconforming mixed finite element methods for the Stokes problem. Math. Methods Appl. Sci. (2014) 37: 937-951. |
[6] | Lowest-order weak Galerkin finite element method for Darcy flow on convex polygonal meshes. SIAM J. Sci. Comput. (2018) 40: 1229-1252. |
[7] | L. Mu, Pressure robust weak Galerkin finite element methods for Stokes problems, SIAM J. Sci. Comput., 42 (2020), B608-B629. doi: 10.1137/19M1266320 |
[8] | Stability and approximability of the P1-P0 element for Stokes equations. Internat. J. Numer. Methods Fluids (2007) 54: 497-515. |
[9] | Stability of the finite elements $9/(4c+1)$ and $9/5c$ for stationary Stokes equations. Comput. $ & $ Structures (2005) 84: 70-77. |
[10] | A Weak Galerkin mixed finite element method for second-order elliptic problems. Math. Comp. (2014) 83: 2101-2126. |
[11] | X. Ye and S. Zhang, A stabilizer-free weak Galerkin finite element method on polytopal meshes, J. Comput. Appl. Math, 371 (2020), 112699. arXiv: 1906.06634. doi: 10.1016/j.cam.2019.112699 |
[12] | X. Ye and S. Zhang, A conforming discontinuous Galerkin finite element method: Part Ⅱ, Int. J. Numer. Anal. Model., 17 (2020), 110-117. arXiv: 1904.03331. |
[13] | X. Ye and S. Zhang, A stabilizer free weak Galerkin finite element method on polytopal mesh: Part Ⅱ, J. Comput. Appl. Math., 394 (2021), 113525, 11 pp. arXiv: 2008.13631. doi: 10.1016/j.cam.2021.113525 |
[14] | X. Ye and S. Zhang, A stabilizer free weak Galerkin finite element method on polytopal mesh: Part Ⅲ, J. Comput. Appl. Math., 394 (2021), 113538, 9 pp. arXiv: 2009.08536. doi: 10.1016/j.cam.2021.113538 |
[15] | X. Ye and S. Zhang, A stabilizer-free pressure-robust finite element method for the Stokes equations, Adv. Comput. Math., 47 (2021), Paper No. 28, 17 pp. doi: 10.1007/s10444-021-09856-9 |
[16] | A 3D conforming-nonconforming mixed finite element for solving symmetric stress Stokes equations. Int. J. Numer. Anal. Model. (2017) 14: 730-743. |
[17] | A new family of stable mixed finite elements for the 3D Stokes equations. Math. Comp. (2005) 74: 543-554. |
[18] | On the P1 Powell-Sabin divergence-free finite element for the Stokes equations. J. Comput. Math. (2008) 26: 456-470. |
[19] | Divergence-free finite elements on tetrahedral grids for $k\geq 6$. Math. Comp. (2011) 80: 669-695. |
[20] | Quadratic divergence-free finite elements on Powell-Sabin tetrahedral grids. Calcolo (2011) 48: 211-244. |
[21] | $C_0P_2$-$P_0$ Stokes finite element pair on sub-hexahedron tetrahedral grids. Calcolo (2017) 54: 1403-1417. |