       NDSolve initial value problem

• To: mathgroup at smc.vnet.net
• Subject: [mg99154] NDSolve initial value problem
• From: Murat Havzalı <gezginorman at gmail.com>
• Date: Wed, 29 Apr 2009 03:46:54 -0400 (EDT)

```Dear Mathematica users;

I am trying to solve liquid heat/mass transfer equation with mixed boundary
conditions.

My code looks like this:

pe=0.5;

u[y]=1-y^2;

sol=NDSolve[

{

pe*u[y]*D[T[x,y],x]==D[T[x,y],y,y],

T[0,y]==Piecewise[{{-y,y<=-1},{0,-1< y<1},{1,1<=y}}],

T[x,1]==1,

(D[T[x,y],y]/.y->-1)==-1

},

T,{x,0,1},{y,-1,1},SolveDelayed->True];

This returns inconsistent initial boundary conditions error.

I also tried to make the piecewise initial condition, a numerical function
namely:

initial[y_?NumericQ]:=Piecewise[{{-y,y<=-1},{0,-1< y<1},{1,1<=y}}]

However this did not work, too. I understand that there is a similar

and I tried my best to convert it to my problem but couldn't. I couldn't
find the code but I also tried to give the

initial piecewise function as a interpolating function, it returned the same
response.

Any help would be appreciated.

Thanks.

Murat Havzal

```

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