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Can I define time step?
Posted 19.09.2011, 02:16 GMT-4 Version 4.1 3 Replies
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Can I define time step?
For example
0<t<1 : time step = 0.001
1<t<5 : time step = 1
5<t<6 : time step = 0.001
Best regards.
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check the "definition - function tab" and fiddle a little with the formulas, it shoudl work out nicely
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Good luck
Ivar
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I defined the analytic function in definition for "ttt"
0.001*(0<t<1)+1*(1<t<5)+0.001*(5<t<6)
0<t<1 : time step = 0.001
1<t<5 : time step = 1
5<t<6 : time step = 0.001
and then typed ttt in generalized alpha transient solver manual time step field.
But i got expression error message.
Can you help?
Best regards, Ji young park
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you can also use "t" and not "ttt" if I understand you right
I would rather write the operator as
f(t) = 0.001+(1-0.001)*(0<t)*(t<5)
you have fewer tests, or with an if(,,) (see the doc)
and then when you call "f(t)" you write "f(t[1/s])" to get a unitless "t" value expressed in seconds (or whatever unit you prefere.
I'm not fully sure the "0<t<1" double boolean is correctly parsed in COMSOL ?
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Good luck
Ivar