Table 1: L 2 and H 1 relative errors and absolute errors of numerical velocity uh.

0.125 0.01575 0.01111 0.09839 0.61764 0.0625 0.0043 0.00304 0.06039 0.37914 0.03125 9.0178E-4 6.37147E-4 0.02602 0.16338 0.025 5.03846E-4 3.55991E-4 0.01806 0.11338 0.02083 3.03229E-4 2.14246E-4 0.01281 0.08044 0.01786 1.95654E-4 1.38239E-4 0.00926 0.05814 0.01563 1.37093E-4 9.68631E-5 0.00681 0.04275 0.01389 1.06511E-4 7.52554E-5 0.00509 0.03198