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sumarna
06/07/12 01:40am

I am having a problem solving coupled equations using NDsolve.
i have tried every thing but still the following error arises;
NDSolve::ivone: Boundary values may only be specified for one independent variable. \
Initial values may only be specified at one value of the other \
independent variable.
my code is as follows
s = 1;
H = 1;
v = 1;
tmax = 3;
zmin = 0;
zmax = 30;
eqn1 = -2*s*D[b[t, z], t] - 2*s*v*D[b[t, z], z] +
D[a[t, z], z, z] - ((c[t, z]^2 + d[t, z]^2)*
a[t, z])/((a[t, z])^2 + (b[t, z])^2)^(1/2) == 0;
eqn2 = 2*s*D[a[t, z], t] + 2*s*v*D[a[t, z], z] +
D[b[t, z], z, z] - ((c[t, z]^2 + d[t, z]^2)*
b[t, z])/(a[t, z]^2 + b[t, z]^2)^(1/2) + b[t, z] == 0;
eqn3 = -H*D[d[t, z], t] +
H^2/2*D[c[t, z], z,
z] + (\[Phi][t, z] - (1 + a[t, z]^2 + b[t, z]^2)^(1/2))*
c[t, z] == 0;
eqn4 = H*D[c[t, z], t] +
H^2/2*D[d[t, z], z,
z] + (\[Phi][t, z] - (1 + a[t, z]^2 + b[t, z]^2)^(1/2))*
d[t, z] == 0;
eqn5 = D[\[Phi][t, z], z, z] - (c[t, z]^2 + d[t, z]^2) + 1 == 0;

sol = NDSolve[{eqn1, eqn2, eqn3, eqn4, eqn5, a[0, z] == 1,
b[0, z] == 0, c[0, z] == 1, d[0, z] == 0, a[t, zmin] == 1,
b[t, zmin] == 0, a[t, zmax] == 1, b[t, zmax] == 0, c[t, zmin] == 1,
d[t, zmin] == 0, c[t, zmax] == 1,
d[t, zmax] == 0, \[Phi][t, zmin] == 1 == \[Phi][t, zmax]}, {a[t,
z], b[t, z], c[t, z], d[t, z], \[Phi][t, z]}, {t, 0, tmax}, {z,
zmin, zmax}]


please help me out.. :(
PS.. i am also attaching my file.

Attachment: file.nb, URL: ,

Subject (listing for 'NDsolve')
Author Date Posted
NDsolve sumarna 06/07/12 01:40am
Re: NDsolve Ahmad 06/14/12 11:47am
Re: Re: NDsolve Sumarna 06/20/12 11:21am
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