# Items tagged with pdepde Tagged Items Feed

### Finite Difference Method for PDE...

Yesterday at 2:37 PM
0 2

Dear all

I have a PDE and its analytical solution. I want to find the numerical solution by Finite Difference Method.

I duscratize the PDE and boundary condition and Could not able to solve them togethe.

Here is the file FEM-Nu.mw

### 2D Boundary conditions in maple...

September 21 2016
1 14

Please, I need assistance with this problem.

Here is the problem I am trying to solve:

restart:
with(plots):
with(LinearAlgebra):
with(PDEtools):
with(Student):

myPDE1 := D11*diff(w(x,y), x$4) + 2*(D12+2*D66)*diff(w(x,y), y$4) + D22*diff(w(x,y), x$2, y$2) - G*diff(w(x,y), x,y)= 0;

pdsolve(myPDE1);

pdsolve(myPDE1, build);

"Boundary conditions";
"(Note:the domain for the problem is a rectangle)";
bc1 := w(0,y) = 0; # @ x=0 edge;
bc2 := w(a,y) = 0;  # @ x=a edge;
bc3 := w(x,0) = 0; # @ y=0 edge;
bc4 := w(x,b) = 0; # @ y=b edge;
bcx1 := -D11*D[2](w)(0,y) - D12*D[2](w)(0,y) = 0; # @ x=0 edge;
bcx2 := -D11*D[2](w)(a,y) - D12*D[2](w)(a,y) = 0; # @ x=a edge;
bcy1 := -D12*D[2](w)(x,0) - D22*D[2](w)(x,0) = 0; # @ y=0 edge;
bcy2 := -D12*D[2](w)(x,b) - D22*D[2](w)(x,b) = 0; # @ y=b edge;

sol := [myPDE1, bc1, bc2, bc3, bc4, bcx1, bcx2, bcy1, bcy2];

pdsolve(sol);

"Note:
and D11, D12, D22, D66 and G are constant.
The intention is to find the critical value for G"

I need help with how I can handle the boundary conditions for the problem. Thanks a million.

### Plotting the solution of a PDE (pdsolve-numeric)...

September 09 2016
0 2

Hello everybody!
I have a PDE with initial and boundary conditions. I want to plot its solution by taking "t" as x axis. I have seen the documentation. It only has the space variable on x axis. Please show me a way to achieve what I intend.

here is the file pdsolve.mw

The value of x can be chosen as 0.16 or 0.21

### pdsolve-numeric error...

September 08 2016
0 11

I am trying to solve a PDE using pdsolve-numeric. I am getting an error related to boundary conditions.
Please see the follwing worksheet and suggest me some solutions

pdsolve.mw

August 24 2016
0 2

### Error, (in pdsolve/numeric/process_PDEs) can only ...

August 24 2016
0 7

hi .may every one help me for pdsolve this differential equations?

all initial boundary condition are zero

thanks...

pdeSol_(1).mw

 > # # Define some parameters #   sigma := 10; N := 0; beta := 1; alpha := 1; PDE1 := diff(w(X, theta, t), X, X, X, X)+2*alpha^2*(diff(w(X, theta, t), theta, theta, X, X))+alpha^4*(diff(w(X, theta, t), theta, theta, theta, theta))-N*(diff(w(X, theta, t), X, X))+diff(w(X, theta, t), t, t)-beta*w(X, theta, t)-sigma = 0
 (1)
 > # # Define the PDES #   PDEs:= { diff(w(X, theta, t), X, X, X, X)+2*alpha^2*(diff(w(X, theta, t), theta, theta, X, X))+alpha^4*(diff(w(X, theta, t), theta, theta, theta, theta))-N*(diff(w(X, theta, t), X, X))+diff(w(X, theta, t), t, t)-beta*w(X, theta, t)-sigma = 0    };
 (2)
 > # # Set of boundary conditions at x=1. #    bcs1:= { D[1](w)(1,theta, t) = 0,               w(1,theta, t) = 0          };
 (3)
 > # # Set of boundary conditions at x=0 #   bcs2:= {    w(0,theta, t)=0,            D[1](w)(0,theta, t)=0          };
 (4)
 > # # Set of boundary conditions at t=0 #   bcs3:= { w(x,theta,0)=0,                       D[2](w)(x,theta,0)=0 };
 (5)
 >
 > pdsolve( PDEs, union(bcs1, bcs2, bcs3), numeric);
 >

### Nonlinear Coupled PDE...

August 17 2016
1 5

Hy Prof.

pde[1] := diff(u(x, t), t)-D(diff(u(x, t), x, x)) = alpha*u(x, t)*(1-v(x, t))

pde[2] := diff(v(x, t), t)-E(diff(v(x, t), x, x)) = beta*v(x, t)*(1-u(x, t))

### Problem with PDE...

August 12 2016
0 3

i have 2 PDE equations with some boundary conditions,maple get me errors, what should i do ? please help
how can i make correction in my system or boundary to have a solution ?

### How to convert PDE to ODE using Lie group...

July 28 2016
1 1

Can some one help me for converting three or two coupled pdes to odes using Lie group or any other method in maple

### Symmetries of strange PDE...

June 29 2016
2 11

I thought about the following PDE:

EDIT: The u(0,t) is not a typo! It is really meant to be part of the PDE!

Latex/Matjax: $$\dfrac{\partial u(x,t)}{\partial t}=\alpha \dfrac{\partial^2 u(x,t)}{\partial x^2}+u(x=0,t).$$

Maple: diff(u(x,t),t)=alpha*diff(u(x,t),x$2)+u(0,t) How can i determine the symmetries of this PDE with Maple? ### How to write boundary condition in pdsolve?... June 21 2016 1 4 I have the PDE u_{xx}+u_{yy} = 1 with BC: u|_{x^2+y^2=1} =0 ; how to write down the command of the BC in solving this PDE?, btw can I make maple show me how to solve this PDE analytically? Thanks in advance. Here are the lines that I wrote so far: pde := diff(u(x, y), x, x)+diff(u(x, y), y, y) = 1; ans := pdsolve(pde) how to add the BC correctly to pdsolve? I am not sure how to write the condition x^2+y^2=1 and that u will get a value on this boundary. ### Solve PDE by Maple... June 20 2016 0 6 Hi all, Please help me with this question. I want to solve a PDE by Maple.  (1)  (2)  (3)  (4) ### How to solve this PDE system?... June 19 2016 0 6 hi .please help me for solve this equations. bbb2.mw  (1)  (2)  (3)  (4)  (5) if former equations are not solvable , please help me for another way, in which at first two equation solve..in this way in equation [J and B] assume that q[311]=e[311]=0 and dsolve perform to find Φ and ψ after by finding Φ and ψ is use for detemine w and u0 please see attached file below[bbb2_2.mw] bbb2_2.mw Download bbb2.mw ### Problem with PDE solution ... June 08 2016 1 8 vz := 2*(-eta^2+1); D_im := .22; r0 := 1; pde := diff(vz*Y(eta, z), z)-D_im*((diff(eta*(diff(Y(eta, z), eta)), eta))/eta+diff(Y(eta, z), $(z, 2)))/r0 = 0;

pde := expand(%);

ibc := [Y(1, z) = 0, (D[1](Y))(0, z) = 0, Y(eta, 0) = 1, (D[2](Y))(eta, 0) = 0];

sol := pdsolve(pde, ibc, numeric, time = z, range = 0 .. 1);

pds := sol:-value(z = 0, output = listprocedure);

sol:-plot(z = 0.1e-3, numpoints = 50, color = blue, view = 0 .. 1)

So I was trying to solve this conservation equation for the radial coordinate eta and the z coordinate being treated as time. The flow is in z direction. Now unfortunately it is diverging. Not sure why though. What am I doing wrong?

May 22 2016
0 5

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