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Error-Failed to find consistent initial values

Posted 22.02.2011, 03:12 GMT-5 RF & Microwave Engineering Version 4.0 6 Replies

SM Ananth
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Hi everyone,
I have a velocity boundary condition in the form of a Fourier series with 8 sine and 8 cosine terms(ie.,8th order Fourier series) to be applied at the inlet of a simple cylindrical geometry and at the exit boundary condition is of a constant pressure value.When I defined this condition at the 'boundary settings dialog box' directly I COULD obtain the solution.

On the other hand when I defined the same boundary condition in the 'Functions' dialog box that we open through 'options' [ie.,options-functions-new-analytic] and providing a function name of 'u',then entering 'u' in the boundary settings dialog box and then trying to solve the problem,the solver is giving the error-'Failed to obtain consistent initial values'. I don't know what went wrong when I tried the same problem through two different ways

And why I am doing this is because ultimately I need to define a 'piecewise analytic' function as my velocity boundary condition which is in the form of a Fourier series with order 8 for one interval and order 12 for the next consecutive interval

Can anyone help me to figure out this error...

thanks
SM Ananth
6 Replies Last Post 08.10.2011, 07:04 GMT-4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 22.02.2011, 04:55 GMT-5
Hi

Are you sure you do not have a naming conflict with COMSOL's internal variables. u is normally the displacement along "x" for COMSOL

--
Good luck
Ivar
Hi Are you sure you do not have a naming conflict with COMSOL's internal variables. u is normally the displacement along "x" for COMSOL -- Good luck Ivar
SM Ananth
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Posted: 1 decade ago 22.02.2011, 05:29 GMT-5
Hello sir,
I checked with the default variable names provided by Comsol to find conflicts if there is any.In page 148 of Comsol Modelling Guide,it has been given that 'u' is the default variable for x component of VELOCITY.So I think the error is not related to variable 'u' being used.

thanks,
SM Ananth
Hello sir, I checked with the default variable names provided by Comsol to find conflicts if there is any.In page 148 of Comsol Modelling Guide,it has been given that 'u' is the default variable for x component of VELOCITY.So I think the error is not related to variable 'u' being used. thanks, SM Ananth
Kai Herbrig
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Posted: 1 decade ago 22.02.2011, 05:48 GMT-5
Obviously there is a naming conflict since you are redefining a variable which is already used by Comsol. (You even checked it)

If you want to assign an internal comsol variable 'u' on the boundary to a specified value, change the function name to maybe 'u_usr'. Then type 'u_usr' (don't forget the arguments) in the field for the expression of 'u'. Never redefine internal variables unless you know exactly what you are doing!
Obviously there is a naming conflict since you are redefining a variable which is already used by Comsol. (You even checked it) If you want to assign an internal comsol variable 'u' on the boundary to a specified value, change the function name to maybe 'u_usr'. Then type 'u_usr' (don't forget the arguments) in the field for the expression of 'u'. Never redefine internal variables unless you know exactly what you are doing!
SM Ananth
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Posted: 1 decade ago 25.02.2011, 04:08 GMT-5
Hi,
Thanks for your suggestion.I could rectify my mistake...
SM Ananth
Hi, Thanks for your suggestion.I could rectify my mistake... SM Ananth
Muhammad Mohsin Rehman
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Posted: 1 decade ago 05.10.2011, 15:04 GMT-4
Hi,

I am receiving an error titling Failed to Find Consistent Initial Values...

Can you suggest some solution.

Thanks in advance.
Hi, I am receiving an error titling Failed to Find Consistent Initial Values... Can you suggest some solution. Thanks in advance.
Muhammad Mohsin Rehman
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Posted: 1 decade ago 08.10.2011, 07:04 GMT-4
Can any body help, please!!!!!!!!!!!
Can any body help, please!!!!!!!!!!!

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