Thank you very much for the answer, but what does this mean in this code example:
pde = {-(1050000/13) D[u[x, y, z], z, z] -
1050000/13 D[u[x, y, z], y, y] - 2625000/13 D[w[x, y, z], x, z] -
2625000/13 D[ v[x, y, z], x, y] -
3675000/13 D[u[x, y, z], x, x] ==
0, -(1050000/13) D[v[x, y, z], z, z] -
2625000/13 D[w[x, y, z], y, z] - 3675000/13 D[v[x, y, z], y, y] -
2625000/13 D[u[x, y, z], x, y] - 1050000/13 D[v[x, y, z], x, x] ==
0,
-(3675000/13) D[ w[x, y, z], z, z] -
2625000/13 D[v[x, y, z], y, z] - 1050000/13 D[w[x, y, z], y, y] -
2625000/13 D[u[x, y, z], x, z] - 1050000/13 D[w[x, y, z], x, x] ==
0}
bcs =
(* 3 Dirichtlet bcs *)
{u[50, y, z] == 0,
v[x, 0, z] == 0,
w[x, y, 70] == 0,
(* 9 Neumann bcs*)
(D[u[x, y, z], y] + D[v[x, y, z], x] == 0) /. {y -> 50},
(3 D[w[x, y,] + 7 D[v[x, y, z], y] + 3 D[u[x, y, z], x] ==
0) /. {y -> 50},
(D[v[x, y, z], z] + D[w[x, y, z], y] == 0) /. {y -> 50},
(3 D[w[x, y, z], z] + 3 D[v[x, y, z], y] + 7 D[u[x, y, z], x] ==
0) /. {x -> 0},
(D[u[x, y, z], y] + D[v[x, y, z], x] == 0) /. {x -> 0},
(D[u[x, y, z], z] + D[w[x, y, z], x] == 0) /. {x -> 0},
(D[u[x, y, z], z] + D[w[x, y, z], x] == 0) /. {z -> 0},
(D[v[x, y, z], z] + D[w[x, y, z], y] == 0) /. {z -> 0},
(10500 D[w[x, y, z], z] + 4500 D[v[x, y, z], y] +
4500 D[u[x, y, z], x] == 13) /. z -> 0}
NDSolveValue[{pde, bcs}, {u, v, w}, {x, 0, 50}, {y, 0, 50}, {z, 0,
70}]
I don't understand the error message here (it is not a Dirichlet boundary condition):
Attachments:
