[讨论]对于courant condition 选取时间步和空间步疑问

离线rechirson

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0楼发表于: 2010-04-09 15:29:25

由courant condition 知道cdt<=dx , 既然dx=cdt 是magic number 所得的解几乎近似解析解那为什么通常大家流通的程式码和一般书籍都选用dx=2cdt 甚至其他的系数不用magic numb ..

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离线katomo

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1楼发表于: 2010-04-10 14:48:43

看看吧(ZT).

(refer to FDTD grid dispersion relation)
A large Courant number is thus desirable for two reasons. First, the larger the Courant number, the greater the temporal step and hence the more quickly a simulation advances (i.e., each update represents a greater advance in time). Second, the larger the Courant number, the smaller the dispersion error. In one dimension a Courant number of unity is the greatest possible and, since there is no dispersion error with this Courant number, the corresponding time step is known as the magic time-step. Unfortunately a magic time-step does not exist in higher dimensions.

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