$\tau$

$\alpha =1.1$

$\alpha =1.5$

$\alpha =1.9$

${\Vert e\Vert }_{L_2}$

order

${\Vert e\Vert }_{L_2}$

order

${\Vert e\Vert }_{L_2}$

order

1/10

3.0243e−05

8.6123e−04

1.4751e−02

1/20

7.5659e−06

1.9990

2.2005e−04

1.9685

4.1567e−03

1.8273

1/30

3.3646e−06

1.9985

9.7893e−05

1.9976

1.8690e−03

1.9713

1/40

1.8931e−06

1.9990

5.5086e−05

1.9986

1.0523e−03

1.9967

1/50

1.2117e−06

1.9995

3.5262e−05

1.9991

6.7370e−04

1.9984