unsteady vs steady
 

Hay everyone, I have a question related to staedy and unsteady flow.
Firstly: I have done a model with similar parametres and calculated until solution converged. I got different answers.
When is useful to use unsteady flow?(or steady)

You set the solver to "unsteady" and the solution converges? Then, your flow is not unsteady. If this is the case, you should get the same results, whether you set it to "steady" or "unsteady". Sounds like you did something wrong.
Post some pictures of your setup.