NDSolve error for partial DV

• To: mathgroup at smc.vnet.net
• Subject: [mg107714] NDSolve error for partial DV
• From: Menl <szegersnl at gmail.com>
• Date: Wed, 24 Feb 2010 06:19:58 -0500 (EST)

```I try to numerically solve a set of 2 DV containing two functions depending on two variables x and t. x represents the position and t represents time.

I have defined several boundary conditions ( for x) and one initial condition ( for t)

However I receive an error from Mathematica so there is obviously some error.

The error is : 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."

The code is as follows:

sw7t = NDSolve[{Bs (D[g[x, t], {x, 2}] - D[w[x, t], {x, 3}]) -
A g[x, t] == 0 //. vars,
A D[g[x, t], {x, 1}] - (Bbot + Btop) D[w[x, t], {x, 4}] - \[Mu] D[
w[x, t], {t, 2}] == 0 //. vars,  w[0, t] == 0, w[3, t] == 0,
D [w[x, t], {x, 2}] == 0 //. x -> 0,
D [w[x, t], {x, 2}] == 0 //. x -> 3,
D [w[x, t], {t, 1}] == 0 //. {t -> 0},
D [g[x, t], {x, 1}] == 0 //. x -> 0,
D [g[x, t], {x, 1}] == 0 //. x -> 3}, {w , g}, {x, 0, 3}, {t, 0,
10}]

Here the constants used are contained in vars and assigned  code.

If someone knows where the mistake I would very much like to know.