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Implement a third order PDE equation
Posted 18 mag 2010, 09:57 GMT-4 3 Replies
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Hello everybody
I am trying to develop numeric models to simulate non-linear acoustic.
I try to implement a third order PDE Equation in PDE module and some users say that it's not possible to implement this kind of equation in comsol. have they reason ?
You can find the equation in the attached file.
I wait for your help if you have any idea.
Thank you.
I am trying to develop numeric models to simulate non-linear acoustic.
I try to implement a third order PDE Equation in PDE module and some users say that it's not possible to implement this kind of equation in comsol. have they reason ?
You can find the equation in the attached file.
I wait for your help if you have any idea.
Thank you.
Attachments:
3 Replies Last Post 20 mag 2010, 02:17 GMT-4
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Posted:
1 decade ago
it is easy, at least algebraically, take for eg v=dp/dtau as a second function and resolve the system for {p, v}.
You have other choices some possibly better than other depending on the domain ad the BC...
BUT it is not clear that comsol solver will resolve that kind of wave equations properly you will need to try and see what you get.. and read carefully doc regarding wave equation at large..
JF
You have other choices some possibly better than other depending on the domain ad the BC...
BUT it is not clear that comsol solver will resolve that kind of wave equations properly you will need to try and see what you get.. and read carefully doc regarding wave equation at large..
JF
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Posted:
1 decade ago
thank you for the reply
I tried to do as you have show me but it does not solve the difficulty of the term d^2(p^2)/dtau^2 because my variable is p and I can't find how to declare a second variable p ^ 2.
I hope you will understand what I want to explain.
I tried to do as you have show me but it does not solve the difficulty of the term d^2(p^2)/dtau^2 because my variable is p and I can't find how to declare a second variable p ^ 2.
I hope you will understand what I want to explain.
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Posted:
1 decade ago
If v=dp/dtau
d(p^2)/dtau= 2pv
d^2(p^2)/dtau^2=2(v^2+p*dv/dtau)
I dont see the ALGEBRAIC problem.
I still have doubt wether or not comsol solver can resolve that kind of equation numerically, but I am sure you can write it in comsol and see what happens.
JF
d(p^2)/dtau= 2pv
d^2(p^2)/dtau^2=2(v^2+p*dv/dtau)
I dont see the ALGEBRAIC problem.
I still have doubt wether or not comsol solver can resolve that kind of equation numerically, but I am sure you can write it in comsol and see what happens.
JF