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Re: problem in apply the numerical flux in PDE

Posted Oct 4, 2013, 7:23 a.m. EDT Results & Visualization Version 3.5a 6 Replies

Jesus Lucio
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Hello,

(This discussion refers to paper in www.comsol.com/paper/3d-simulation-of-action-potential-propagation-in-a-squid-giant-axon-7317)

Perhaps I'm mistaken, but I think that there is an error in the paper.
For me, it would be better to include
, i.e. let it as it comes by default, and
(this as there's no laplacian term for ).

And I would change F (the source term), to the rest of terms in equations (1) and (2):
, and
.

If one does what authors say in equations (4) and (5), all those terms would be affected by the divergence operator (acting on ), and that's not possible (as they are scalars, not vectors, and the result, if possible, would be different from what appears in equations (1) and (2)).

Regards,
Jesus.
6 Replies Last Post Apr 18, 2014, 11:25 a.m. EDT
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Guneet Bedi
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Posted: 1 decade ago Nov 21, 2013, 5:07 p.m. EST
I'm using the equations as suggested by you for numerical flux. It gives me an error that the unit is not correct. Also what value of I should I take in the expression?

Thanks
I'm using the equations as suggested by you for numerical flux. It gives me an error that the unit is not correct. Also what value of I should I take in the expression? Thanks
Jesus Lucio
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Posted: 1 decade ago Nov 22, 2013, 6:12 a.m. EST
Hi,
I understand from the article that in equation (1) is the same as in eq. (8). Both physics (PDE Mode, for eqs. (1) and (2), and electrostatics, eq. (8)), seem to be solved simultaneously.
Hi, I understand from the article that [math]I[/math] in equation (1) is the same as [math]V[/math] in eq. (8). Both physics (PDE Mode, for eqs. (1) and (2), and electrostatics, eq. (8)), seem to be solved simultaneously.
Guneet Bedi
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Posted: 1 decade ago Nov 22, 2013, 6:47 a.m. EST
I'm attaching my model here. I'm not being able to simulate it for some unknown reason. Can you take a look at it and let me know what I may be doing wrong. I'm trying to follow the paper exactly but still finding it difficult to simulate the model.

Thanks.
I'm attaching my model here. I'm not being able to simulate it for some unknown reason. Can you take a look at it and let me know what I may be doing wrong. I'm trying to follow the paper exactly but still finding it difficult to simulate the model. Thanks.

Attachments:

Guneet Bedi
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Posted: 1 decade ago Nov 24, 2013, 10:16 a.m. EST
Hi,
What would be the unit of the source term (F)? I've selected the unit of the dependent variables u1 and u2 as volts (V). Is that fine?
Hi, What would be the unit of the source term (F)? I've selected the unit of the dependent variables u1 and u2 as volts (V). Is that fine?
Guneet Bedi
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Posted: 1 decade ago Nov 24, 2013, 10:30 a.m. EST
Also, F1 specified by you gives an error that it has an inconsistent unit. Do help regarding that.

Thanks
Also, F1 specified by you gives an error that it has an inconsistent unit. Do help regarding that. Thanks
Amir Bayat
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Posted: 1 decade ago Apr 18, 2014, 11:25 a.m. EDT
hi
i have same problem with simulation of this paper.
i don't know where the Γ would be applied:
Γ = Δu1 +(α − u1 )(u1 −1 )u1 +( −u2 )+I
Γ = ε(βu1 − γu2 − δ)
also my model has this errors in final :
Error:
Failed to find consistent initial values.
Undefined_value_found_Linsolv
NaN_or_Inf_found_when_solving_linear_system_using_SOR
Last time step is not converged.

please help me.
hi i have same problem with simulation of this paper. i don't know where the Γ would be applied: Γ = Δu1 +(α − u1 )(u1 −1 )u1 +( −u2 )+I Γ = ε(βu1 − γu2 − δ) also my model has this errors in final : Error: Failed to find consistent initial values. Undefined_value_found_Linsolv NaN_or_Inf_found_when_solving_linear_system_using_SOR Last time step is not converged. please help me.

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