Table 5 The space order of convergence and mass errors of the scheme

t = 0.01

\(L^{2}\)-norm-

7.2729E−4

1.8295E−4

4.5442E−5

1.9918E−5

order

–

1.9911

2.0094

2.0342

mass error

5.9008E−15

1.9856E−15

1.8239E−16

3.7283E−16

t = 0.02

\(L^{2}\)-norm-

1.3843E−3

3.4802E−4

8.6450E−5

3.7907E−5

order

–

1.9919

2.0092

2.0333

mass error

1.5327E−14

3.6242E−15

1.4922E−15

4.8240E−16

t = 0.05

\(L^{2}\)-norm-

3.0027E−3

7.5398E−4

1.8734E−4

8.2224E−5

order

–

1.9937

2.0089

2.0309

mass error

2.0386E−14

2.5691E−15

1.7195E−15

1.8908E−17