| Scheme | Grids | L1 error | L1 order | L∞ error | L∞ order |
| P2 | 40 | 7.8257 × 10−4 | —— | 1.2529 × 10−3 | —— |
|
| 80 | 9.7962 × 10−5 | 2.9985 | 1.5995 × 10−4 | 2.9702 |
|
| 160 | 1.2319 × 10−5 | 2.9919 | 2.0824 × 10−5 | 2.9418 |
|
| 320 | 1.5768 × 10−6 | 2.9664 | 2.8129 × 10−6 | 2.8887 |
|
| 640 | 2.1549 × 10−6 | 2.8719 | 4.0568 × 10−7 | 2.7942 |