Bill Greene

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How to input a novel boundary condition for a coupled PDE system
Here is my code to solve this problem with pde1dm based on my understanding of the description and included code. I'm not at all...

3 months ago | 0

Answered
I am trying to solve the system of coupled partial differential equations described in the attachment using the function pdepe. My code runs into this error:
The reason for the error you are getting is that your boundary condition definition (p=0 and q=0) is invalid. I modified your p...

3 months ago | 1

Answered
How to solve the following PDE equation
I don't know how to evaluate that integral using pdepe. However, I have written a pde solver (pde1dm) that has an input syntax v...

5 months ago | 0

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pde1dm with coupled ODEs
Your second equation is an elliptic PDE NOT an ODE because both unknown variables are functions of both x and t.. Accordingly, p...

10 months ago | 0

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pde1dm compared to pdepe
There are several differences in the pde1dm spatial discretization compared with pdepe. For the m=0 case (Cartesian), both pde1...

10 months ago | 1

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pdepe with cross elements in the differentiation "c"
If you are willing to consider an alternative to pdepe, I have written a PDE solver that mostly supports the same input syntax a...

1 year ago | 1

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Left Boundary Condition of the pdepe for solving Spherical Coordinates Diffusion Equation
When the model geometry is cylindrical or spherical, the mathematically well-posed boundary condition at r=0 is the symmetry ...

1 year ago | 1

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How to solve a PDE where the boundary condition is an spatial ODE
I suggest you use the pdepe function to solve this PDE. In PDE of the type you show, especially when the PDE represents a ph...

1 year ago | 0

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Initial conditions for PDEPE
The problem is that you are using an old, undocumented form of the of the pdepe function to pass additional parameters to the f...

1 year ago | 1

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How do I solve this 1D transient convection-diffusion equation with the convection term coupled with transient boundary values?
I have created a PDE solver (pde1dm) that is similar to pdepe but includes some enhancements such as the capability to add some...

2 years ago | 0

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Answered
Hello everyone I hope you are all doing well. Please I have a concern about the coupling of an ODE and an EDP.
I looked at your mathematical description of this problem.Since T is a function of z, V and u are also functions of z. So you re...

2 years ago | 0

Answered
How to couple interface of two domains in MATLAB?
As I said, I believe that the expression for S in your definition of the problem is not correct and your explanation did not rea...

2 years ago | 0

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Computing temperature of a fluid inside a cylinder using PDEPE
I have written a 1D PDE solver that has an input syntax similar to pdepe but has some additional enhancements including the cap...

2 years ago | 1

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Answered
pdepe extract intermediate values
I have written a PDE solver, pde1dm, that has some similarities to pdepe and accepts the same input syntax as pdepe. Most input ...

2 years ago | 0

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Answered
Solving partial differential equations using pdesolver
First, in your call to pdepe, you have the t and z arguments switched. It should be sol=pdepe(m,@pde1, @pde1ic, @pde1BC,z,t); ...

2 years ago | 0

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pdepe help! The solution gives 0...
If you are solving a PDE with either cylindrical symmetry (m=1, your case) or spherical symmetry (m=2), and your left boundary ...

2 years ago | 0

Answered
Pdepe: Spatial discretization has failed. Discretization supports only parabolic and elliptic equations, with flux term involving spatial derivative.
Your definition of the input arguments for the boundary condition function is incorrect. Replace, function [pl,ql,pr,qr] = pde...

3 years ago | 0

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Answered
Solving coupled set of PDEs and ODEs for 1D-problem using pde1dM
Because your equation (2) is a PDE and not an ODE (as I pointed out in your previous post), it will be quite challenging to sol...

3 years ago | 0

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Why does pdepe throw an error depending on boundary condition parameters?
Interesting. The ODE solver(ode15s) is numerically approximating the iteration matrix for the PDE and, due to roundoff er...

3 years ago | 0

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How to deal these type of errors from pdepe? "Error in pdepe/pdeodes (line 359)"
Yes, in my example, the M-matrix was constant but the same idea applies if M is a function of x or the dependent variables. The ...

3 years ago | 0

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How to deal these type of errors from pdepe? "Error in pdepe/pdeodes (line 359)"
pdepe does not accept a non-diagonal mass matrix. But often you can deal with this by calculating the inverse of the mass matrix...

3 years ago | 0

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Answered
Why does solving the heat equation with MATLAB (pdepe) yield a completely different result than the Heisler chart (analytical solution)?
I referred to section 5.5 of Bergman (the source of your pdf file) and wrote a function that computes the solution the Heisler c...

3 years ago | 0

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PDEPE: Unable to meet integration tolerances without reducing the step size below the smallest value allowed
I have occasionally seen similar problems with pdepe in the past. I have written a PDE solver that has input similar to pdepe...

3 years ago | 0

Answered
Solving a system a coupled ODE and PDE
The error message is caused by your definition of the ode function: function [dydt] = ode_syst2(t, Tg, Ts, Fig, Fis) The defin...

4 years ago | 0

Answered
Appropriate method for solving coupled pdes
Yes, although it is true that the documentation for pdepe describes it as a solver for parabolic systems, it can often obtain...

4 years ago | 2

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Answered
Solving PDEs with mass conservation
I don't know how to integrate the dependent variables using pdepe. However, I have written a PDE solver with an input syntax sim...

4 years ago | 0

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Answered
Pdepe: Spatial discretization has failed. Discretization supports only parabolic and elliptic equations, with flux term involving spatial derivative.
The boundary conditions for your second PDE are invalid. These should work: pl = [0; 0]; ql = [1; 1]; pr = [ur(1)-cAO; 0]; q...

4 years ago | 1

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Answered
A system of PDEs which have one PDE with a spatial variable fixed term, u(x0, t)
pdepe is not really designed to handle systems of coupled PDE and ODE. However, I have written a PDE solver for MATLAB that has ...

4 years ago | 0

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Answered
Spatial discretization has failed. Discretization supports only parabolic and elliptic equations, with flux term involving spatial derivative.
Your boundary conditions for u2 (q=0, p=0 at each end) are not valid. The second equation in your system (u2_t=...) is, in fact...

4 years ago | 0

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Answered
Gas-Solid Reaction Modeling with Random Pore Model. Pdepe: Spatial discretization has failed. Discretization supports only parabolic and elliptic equations, with flux term involving spatial derivative.
Your right-end boundary conditions are invalid. Possibly you want: pr=[ur(1)-1 0]'; qr =[0 1]' ;

4 years ago | 1

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Bill Greene

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