It doesn't have to be a real container to contain it it's just an imaginaryboundary there.
它不必是,一个真实的容器,只是一个想象的边界。
2
The method of solving the implicit scheme of difference equations by means of imaginaryboundary condition was proposed.
提出了应用“假想边界”求解数学模型的隐式差分格式的方法。
3
The area is filled if the number of boundary lines going in one direction (relative to the imaginary line) is not equal to the number of boundary lines going in the other direction.