“…In the following examples, we set µ = 1 and ρ = 1. The Darcy-Forchheimer coefficient are taken to be β = β 0 κ −1 [13,29,30], where the parameter β 0 control the influence of the nonlinear term and we will test cases with β 0 = 1, β 0 = 10, β 0 = 100, β 0 = 1000 and β 0 = 10000, respectively. Denote the fine-grid solution by (p f , u f ), suppose the multiscale solution is denoted by (p ms , u ms ), then the relative L 2 errors for pressure and velocity are denoted as follows Erp(p ms ) := p ms − p f / p f and Eru(u ms ) := u ms − u f / u f .…”