Meshgrid

21 × 21

21 × 41

41 × 41

41 × 51

41 × 81

51 × 51

51 × 81

81 × 81

Nu

3.1203

3.2509

3.2273

3.2220

3.2130

3.2173

3.2061

3.1985

Time computing

14

15

45

55

88

85

133

334

$\overline{\delta }\left(\%\right)$

2.44

1.64

0.9

0.73

0.45

0.59

0.24

0