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MathGroup Archive 1997

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Problems with NDSolve

  • To: mathgroup at smc.vnet.net
  • Subject: [mg5991] Problems with NDSolve
  • From: lichtner at swri.edu
  • Date: Sat, 8 Feb 1997 22:38:09 -0500
  • Organization: Southwest Research Institute
  • Sender: owner-wri-mathgroup at wolfram.com

I'm having problems with using NDSolve to solve partial differential
equations. Has anyone had any luck with with??
I tried a very simple heat conduction equation as a test with constant
initial temperature and constant temperature at the left face, and a zero 
flux boundary condition at the right face:

soln =NDSolve[{D[y[x,t], t] == D[y[x,t], x, x],
y[0,t]==1, y[x,0]==0, 
Derivative[1,0][y][5,t]==0},
y[x,t], {x,0,5}, {t,0,10}]

I get a strange warning message:

NDSolve::"ibcinc": 
    "Warning: Boundary and initial conditions are inconsistent."

And after plotting the results with

Plot3D[Evaluate[y[x,t] /. First[soln]],
	{x,0,5}, {t,0,10},PlotPoints->30]

get just a flat surface with nothing happening!

Thanks for any help.
...Peter
 
__________________________________________________________________
Peter C. Lichtner	<lichtner at swri.edu>
Southwest Research Institute		http://www.swri.edu/
Center for Nuclear Waste Regulatory Analyses (CNWRA)
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Telephone:	Work:	(210) 522-6084	<<NeXTMail Welcome!!!>>
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