iter

h

$\Vert \nabla \left(u-u_h\right)\Vert$

$\Vert u-u_h\Vert$

$\Vert {\nabla }_{\tau }\left(u-Q_{\tau }{u}_h\right)\Vert$

$\Vert u-Q_{\tau }{u}_h\Vert$

1

2⁻³

0.1196e−0

0.7787e−2

0.5207e−1

0.7456e−2

2

3⁻³

0.3555e−1

0.6966e−3

0.8137e−2

0.6649e−3

3

4⁻³

0.0150e−1

0.1241e−3

0.2481e−2

0.1184e−3

4

5⁻³

0.7680e−2

0.3255e−4

0.1014e−2

0.3108e−4

5

6⁻³

0.4445e−2

0.1090e−4

0.4906e−3

0.1040e−4

$O\left(h^r\right)$

0.9990

1.9941

1.4117

1.9953