[求助] airpak simulation 求助

airpollution

我用airpak模拟一个exhaust hood 前方的气流速度分布图，并且比较不同grid number 下，得结果与实验结果的关系，理论上网格数越多，结果越好，但是我的结果是：30万的网格数 结果比10万和90万，130万的网格数的结果都要好，请问是哪位能给我一些指教，我会把我的模拟给您发送过去让您指点一下！
i simulated a velocity distribution in front of a exhaust hood surface.
and then i conpared the results under different grid number. the results were the first resut of grid number=300000 were better than any other condition including grid number=100000,900000,1300000,
i have not gotten any idea about it !
who can help me ?
thank you first!