Influence of time step size

Martin_Sz · September 30, 2014, 03:01

Hi All,
I have a question.
I make a transient simulation of heating process. I have fan on the bottom of the model. Radial velocity of this fan is -147 rad/s.
Is time step size have influence on the mass flow value on the domain induced by fan?
For the example
Process time is 4,5 h - time step size 1 min
Process time is 4,5 h - time step size 1 second

Best regards

Martin_Sz · October 2, 2014, 03:27

Any Have experience with this?

ghorrocks · October 5, 2014, 08:29

I think you have missed the point of setting time step sizes. The necessary time step size is a function of many things. So if you have changed something important then you will need to do a time step size sensitivity study the find a new time step size.

Or even better, use adaptive time step size homing in on 3-5 coeff loops per iteration and let the solver find its own time step size.

Martin_Sz · October 6, 2014, 03:40

thanks Glenn very much for your reply

October 5, 2014, 08:29		#3
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	I think you have missed the point of setting time step sizes. The necessary time step size is a function of many things. So if you have changed something important then you will need to do a time step size sensitivity study the find a new time step size. Or even better, use adaptive time step size homing in on 3-5 coeff loops per iteration and let the solver find its own time step size. Martin_Sz likes this.

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October 2, 2014, 03:27		#2
Martin_Sz Senior Member Marcin Join Date: May 2014 Location: Poland, Swiebodzin Posts: 313 Rep Power: 13	Any Have experience with this?

October 6, 2014, 03:40		#4
Martin_Sz Senior Member Marcin Join Date: May 2014 Location: Poland, Swiebodzin Posts: 313 Rep Power: 13	thanks Glenn very much for your reply