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NDSolve
*To*: mathgroup at smc.vnet.net
*Subject*: [mg15118] NDSolve
*From*: Paula Chammas <chammas at dbag.bln.daimlerbenz.com>
*Date*: Sat, 12 Dec 1998 03:59:16 -0500
*Sender*: owner-wri-mathgroup at wolfram.com
Dear all,
I am having a problem with NDSolve.
I am trying to solve the following problem:
Tin[t_] := - 2 t + 12 /; t >= 5 && t <= 6 Tin[t_] := 2 /; t >=
0 && t <= 5 Tin[t_] := 0 /; t >= 6 && t <= 10
Fn[t_] := 0.785 t /; t >= 0 && t <= 2 Fn[t_] := 1.57 t /; t >= 2 &&
t <= 5 Fn[t_] := 0.785 t + 5.495 /; t >= 5 && t <= 7 Fn[t_] := 0
/; t >= 7 && t <= 10
If [ (w[t] ! = v[t]) && ( ( (5/6) Tin[t] - (9/6) w[t] ) > Fn[t] ),
NDSolve[
{ w'[t] + 2 w[t] - Tin[t] + Sign[ w[t] - v[t] ] (2/3)
Fn[t] == 0,
5 v'[t] + v[t] - Sign[ w[t] - v[t] ] (2/3)
Fn[t] == 0,
w[0] == 0, v[0] ==0, {w, v}, {t, 0, 10}
],
NDSolve [
{ 6 w'[t] -Tin[t] - 3w[t] == 0, w[0] ==0, w, {t, 0,
10 }
]
There is a discontinuity at about t =4.08--that is when w[t] = v[t] and
when the switching should happen. I am having problems imposing the
constraints!
Any ideas?
Thanks
Cheers
Paula
--------------------------------------
Paula Chammas
DaimlerChrysler
Research and Technology
Alt-Moabit 96A Tel: +49 30 39982 219 10559 Berlin
fax: +49 30 39982 107
paula.chammas at daimlerchrysler.com
_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Worry is like a rocking
chair - it gives you something to do but it doesn't get you anywhere.
-Dorothy Galyean
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