Difference between steady and transient problems

Jianping Zhang

Hi,

I am fresh to CFD modelling. Could someone please tell me how to judge whether a problem is steady or transient?

As far as I know, for the transient problem, the calculation is performed during each time step until the convergence is achieved, then calculation is moved to the next time step and the programme never stops; for the steady problem, the time step is set to be infinite large, so that the programme stops when it converges.

I have modelled the Ch4 pool fire for both steady and transient problems, and the results are very similar. So what is the point to perform the transient calculation?

Thanks very much for your help

Jianping