[lost.identity]

I'm trying to study head conduction in a duct, in which the heat generation is a function of time. So I'm running unsteady calculations using dual-time stepping.

I understand that the physical time step has to be close to a CFL of 1 and when I increased the time step to a CFL greater than 1 it did not give a physical solution.

My question is does the same thing apply when it's less than CFL of 1? I'm asking this because I tried a CFL of 0.1 and the solution wasn't physical.

Thanks.