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Piecewise function

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Hi, Forum,

I tried two ways for specifying time varying mass flux boundary condition and got different results.

In the first way, I specify it directly as
6000*(t>=0[d]&&t<50[d])+4000*(t>=50[d] && t<75[d])

In the second way, I specify it using a piecewise function func

Start End Function
0 50 6000
50 75 4000

and then use func(t]1/d]) in the mass flux text field.

I wonder if someone has encountered this problem before.

Thanks.

2 Replies Last Post Apr 20, 2014, 10:54 a.m. EDT

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Posted: 1 decade ago Jul 19, 2012, 3:53 p.m. EDT
Well. I figured out the answer to my prev post. By default, COMSOL extrapolates for the whole simulation range. So must provide explicit values for all time periods.
Well. I figured out the answer to my prev post. By default, COMSOL extrapolates for the whole simulation range. So must provide explicit values for all time periods.

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Posted: 1 decade ago Apr 20, 2014, 10:54 a.m. EDT
HI Forum;
I need a help about how to solve a problems with piecewise functions proprieties in comsol 3.5a version
Thanks for the help.
HI Forum; I need a help about how to solve a problems with piecewise functions proprieties in comsol 3.5a version Thanks for the help.

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