A strongly symmetric stress approximation is proposed for the Brinkman equations with mixed boundary conditions. The resulting formulation solves for the Cauchy stress using a symmetric interior penalty discontinuous Galerkin method. Pressure and velocity are readily post-processed from stress, and a second post-process is shown to produce exactly divergence-free discrete velocities. We demonstrate the stability of the method with respect to a DG-energy norm and obtain error estimates that are explicit with respect to the coefficients of the problem. We derive optimal rates of convergence for the stress and for the post-processed variables. Moreover, under appropriate assumptions on the mesh, we prove optimal $ L^2 $-error estimates for the stress. Finally, we provide numerical examples in 2D and 3D.
Citation: Salim Meddahi, Ricardo Ruiz-Baier. A new DG method for a pure–stress formulation of the Brinkman problem with strong symmetry[J]. Networks and Heterogeneous Media, 2022, 17(6): 893-916. doi: 10.3934/nhm.2022031
A strongly symmetric stress approximation is proposed for the Brinkman equations with mixed boundary conditions. The resulting formulation solves for the Cauchy stress using a symmetric interior penalty discontinuous Galerkin method. Pressure and velocity are readily post-processed from stress, and a second post-process is shown to produce exactly divergence-free discrete velocities. We demonstrate the stability of the method with respect to a DG-energy norm and obtain error estimates that are explicit with respect to the coefficients of the problem. We derive optimal rates of convergence for the stress and for the post-processed variables. Moreover, under appropriate assumptions on the mesh, we prove optimal $ L^2 $-error estimates for the stress. Finally, we provide numerical examples in 2D and 3D.
Flow on a maze-shaped domain. Heterogeneous permeability distribution, zoom to visualize the simplicial barycentric trisected mesh, Cauchy stress magnitude, first post-process of velocity, and post-processed pressure
Channel flow with permeability from the SPE10–layer 45 benchmark data, and using a twice quadrisected crisscrossed mesh. Heterogeneous permeability distribution in log scale, Cauchy stress magnitude in log scale, and line integral convolution of second post-process of velocity in log scale
Channel flow with synthetic permeability. The mesh is of simplicial barycentric quadrisected type. Heterogeneous permeability distribution, contour iso-surfaces of velocity magnitude in log scale, and velocity streamlines