what is the physical difference bt steady and transient in solar still modeling
 

hello every body

In the experiment of solar still it is put in the sun for example from 08:00 AM to 05:00 PM

in the modeling by fluent what is the physical difference bt. steady and transient time solver

how the program deals with it if steady and if transient

and how i put that period in the fluent from 08:00 AM to 05:00 PM

thanks in advance