Re: NDSolve system of partial eqn
- To: mathgroup at smc.vnet.net
- Subject: [mg66396] Re: NDSolve system of partial eqn
- From: "Jens-Peer Kuska" <kuska at informatik.uni-leipzig.de>
- Date: Thu, 11 May 2006 02:15:59 -0400 (EDT)
- Organization: Uni Leipzig
- References: <e3sh0g$lu0$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi, you have the solution for \[Phi][z,t] but you ask NDSolve[] to find it and NDSolve[] don't like this, eliminate \[Phi][z,t] and it should work Regards Jens "Peter Breitfeld" <phbrf at t-online.de> schrieb im Newsbeitrag news:e3sh0g$lu0$1 at smc.vnet.net... | | I want to solve the following system of partial deqns . | | \[Mu] = 0.01; | \[Gamma] = 0.03; | \[Rho] = 1000; | Subscript[\[Delta], \[Epsilon]] = 0.171; | K = 0.008; | g = 9.81; | Subscript[k, \[Alpha]] = 1.52; | | Subscript[L, 0] = 0.0003; | Subscript[D, eff] = 3.7/10^9; | Subscript[\[Epsilon], 0] = 0.1; | H = 1; | Subscript[t, max] = 1000; | | eqn1 = D[\[Epsilon][z, t], t] + D[\[Phi][z, t], z] == 0; | eqn2 = \[Phi][z, t] == (K*L[z, t]^2*\[Epsilon][z, t]^(3/2)*(\[Rho]*g + | Subscript[\[Delta], \[Epsilon]]^(1/2)*\[Gamma]* D[1/(L[z, t]* | \[Epsilon][z, t]^(1/2)), | z]))/\[Mu]; | | eqn4 = D[L[z, t], t] == Subscript[D, eff]* ((1 - Subscript[k, \[Alpha]]* | \[Epsilon][z, t]^(1/2))^2/ L[z, t]); | | NDSolve[{eqn1, eqn2, eqn4, | \[Epsilon][z, 0] == Subscript[\[Epsilon], 0], | L[z, 0] == Subscript[L, 0], | \[Phi][-H, t] == 0, | \[Phi][0, t] == 0}, | {\[Epsilon], \[Phi], L}, {z, -H, 0}, | {t, 0, 1}] | | Trying to solve this, I get the Error "NDSolv::ivone", but I don't | really understand what I did wrong. Can someone please explain it to me? | | Gruss Peter | -- | ==-==-==-==-==-==-==-==-==-==-==-==-==-==-==-==-==-==-==-==-==-== | Peter Breitfeld, Bad Saulgau, Germany -- http://www.pBreitfeld.de |