transient simulation
 

how we can decide that the simulation will be transient or steady state? i am modeling a turbine and i need to know that what is the main difference b/w steady and transient state modeling in terms of physics???/

Mathematically: For a steady state run the time derivative of all variables tends to zero. Transient runs have non-zero time derivatives.

Practically: A converged steady run is the same forever and never changes. Transient runs keep changing.

Simulations: A steady state run will converge if simulated by a steady state or a transient run (as the transient run will just converge to the steady solution). A transient run will only converge if simulated transient, and will not converge if simulated steady state.