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

0.1162e−0

0.7440e−2

0.8059e−1

0.7070e−2

2

3⁻³

0.3444e−1

0.6787e−3

0.1389e−1

0.6415e−3

3

4⁻³

0.1452e−1

0.1211e−3

0.4342e−2

0.1144e−3

4

5⁻³

0.7439e−2

0.3178e−4

0.1787e−2

0.3000e−4

5

6⁻³

0.4305e−2

0.1064e−4

0.8670e−3

0.1005e−4

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

0.9999

1.9880

1.3726

1.9899