Numerical integration in the DGFEM for nonlinear convection-diffusion problems

The effect of numerical integration in the DGFEM for nonlinear convection-diffusion problems in 2D is studied. The volume and line integrals in the space semidiscretization are evaluated by numerical quadratures. The main goal is to estimate the error caused by the numerical integration and to show what numerical quadratures should be used in order to preserve the accuracy of the method with exact integration.