how to stop the simulation automatically
 

Dear Alexey,
Thank you for the reply.
The final object is to realize that: the simulation stops once the residuals are smaller than the tolerance.
How to achieve this without using the residualContol, since this function is not applicable to icoFoam?
Thank you for any help.
Best Regards,
Bill

The question is in fact: why do you need to use icoFoam? Why you do not want to use pimpleFoam, which has residual control functionality?

If you would like to entertain yourself, then:

1. There is residual function object, which writes residuals for given fields to postProcessing/residuals/<time> folders.
2. There is systemCall function object, which can do almost anything. For example read last value of residuals from residuals function objects output and create file .CONVERGED in case folder.
3. There is abort function object, which can abort calculation if certain file is present in the case folder.