LMA(Local Mean Age)

JosephKim · April 23, 2012, 23:43

I can't understand the LMA(Local Mean Age)..

Does the LMA means average time of streams that through from the local region to the exit?
I extract cutplot by LMA, but I can't analyse the result.

And I can't understand that meaning of 'Physical time', 'Manual time step'..
Time, time, time.. I am confused with these concepts, please explain to me.

Boris_M · May 4, 2012, 15:25

Hi Joseph,
please check the technical references document. There you'll find an explanation on how it is calculated.

Physical time is the time that you would simulate the reality. For example the time the car would sit in the sun and it heating up.

Manual time step can be set so the solver is not chosing automatically how big the steps shall be, because this can then be often in microseconds instead of seconds or larger. But you have ti be carefull as the solver has to capture the physics that is happening in the calculation. For example if you make to big steps, you will want to get to a faster solution but you will simply jump a time span that is far to big for the solver to predict what would happen between the two points in time and it can cause a crash of the solver. So use this parameter with care and an understanding how big the changes over time will be in your calculation.

Boris

April 23, 2012, 23:43	LMA(Local Mean Age)	#1
JosephKim New Member WookJin Kim Join Date: Feb 2012 Posts: 23 Rep Power: 14	I can't understand the LMA(Local Mean Age).. Does the LMA means average time of streams that through from the local region to the exit? I extract cutplot by LMA, but I can't analyse the result. And I can't understand that meaning of 'Physical time', 'Manual time step'.. Time, time, time.. I am confused with these concepts, please explain to me.

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May 4, 2012, 15:25		#2
Boris_M Disabled Join Date: Jul 2009 Posts: 616 Rep Power: 23	Hi Joseph, please check the technical references document. There you'll find an explanation on how it is calculated. Physical time is the time that you would simulate the reality. For example the time the car would sit in the sun and it heating up. Manual time step can be set so the solver is not chosing automatically how big the steps shall be, because this can then be often in microseconds instead of seconds or larger. But you have ti be carefull as the solver has to capture the physics that is happening in the calculation. For example if you make to big steps, you will want to get to a faster solution but you will simply jump a time span that is far to big for the solver to predict what would happen between the two points in time and it can cause a crash of the solver. So use this parameter with care and an understanding how big the changes over time will be in your calculation. Boris