“…Many researchers aim at studying the efficient numerical methods for quasi-Newtonian flows and related problems, such as the conforming and nonconforming finite element method [4,6,17], the mixed finite element method [5,21,22], the dual-mixed finite element method [18,31], the discontinuous Galerkin (DG) method [13,16,26,27], the weak Galerkin method [43] and the virtual element method [14,25] and so on. Traditionally, the numerical methods are studied based on the velocity-pressure variational formulation, where the velocity and the pressure are the main unknowns [8,11].…”