Distorted square mesh

NE

h

${\Vert u-u_h\Vert }_0$

Rate

100

1.000E−01

5.82184E−03

400

5.000E−02

6.98085E−04

3.06

900

3.333E−02

2.03451E−04

3.04

1600

2.500E−02

8.66004E−05

2.97

Lloyd mesh

NE

h

${\Vert u-u_h\Vert }_0$

Rate

100

1.000E−01

2.65768E−03

400

5.000E−02

3.18677E−04

3.06

900

3.333E−02

9.55500E−05

2.97

1600

2.500E−02

4.04384E−05

2.99