图

$u\left(x,y,0\right)$

图1~3

$u=ones\left(N\right)+\text{sech}\left(x^2/0.02-9+2y/0.01\right)$

图4、图5

$u=\sin \left(x^2/0.02-9+2y/0.01\right)$

图6、图7

$u=\sin \left(\exp \left({\left(x-0.4\right)}^2+{\left(y+0.4\right)}^2\right)\right)-\sin \left(\cos \left({\left(x+0.4\right)}^3+{\left(y-0.4\right)}^2\right)\right)$

图8、图9

$u=\text{sech}\left({\left(-x^3-y^5\right)}^3\right)$

图10、图11

$u=\cos \left(\sin \left(-x^3+y^5\right)\right)$