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Failed to find consistent initial values on FSI simulation

Posted 8 sept. 2009, 22:13 UTC−4 Version 4.3a 6 Replies

Lathi Ton
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I was trying to simulate a FSI problem by modifying the COMSOL FSI example, trying to see the same effect presented in the following reference:

Zhiyong Li, Simulation of the Interaction between Blood Flow and Atherosclerotic Plaque, Proceedings of the 29th Annual International Conference of the IEEE EMBS Cité Internationale, Lyon, France, August 23-26, 2007.

It creates a plaque with cap and core of different Young's moduli, and computes the interaction of them with the blood flow. The model is shown in the attached picture.

In my modified model, when the simulation starts it reports

Failed to find consistent initial values.
Last time step is not converged.

Any trick to define the boundary conditions? I've tried composite and assembly geometries with no vail.

Thanks.
Lathi.

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6 Replies Last Post 2 sept. 2014, 22:03 UTC−4
Yuanhong Dong
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Posted: 1 decade ago 8 sept. 2009, 23:22 UTC−4
try a new solver, or u check the scalars u typed, especially the orders of the scalars and constants.
try a new solver, or u check the scalars u typed, especially the orders of the scalars and constants.
Juan Anza
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Posted: 1 decade ago 12 sept. 2009, 05:16 UTC−4
If it is a transient analysis try to smooth in time the velocity inlet input multiplyng by a continuos step as
flc1hs(t-0.1,0.1)
If it is a transient analysis try to smooth in time the velocity inlet input multiplyng by a continuos step as flc1hs(t-0.1,0.1)
Maral Hassani
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Posted: 1 decade ago 13 juil. 2010, 08:35 UTC−4
hi Lathi
Did you solve your problem?I encounter the same error as u did in my FSI model and I dont know how to solve it!
whould you please help me?
I would be very thankful
maral





I was trying to simulate a FSI problem by modifying the COMSOL FSI example, trying to see the same effect presented in the following reference:

Zhiyong Li, Simulation of the Interaction between Blood Flow and Atherosclerotic Plaque, Proceedings of the 29th Annual International Conference of the IEEE EMBS Cité Internationale, Lyon, France, August 23-26, 2007.

It creates a plaque with cap and core of different Young's moduli, and computes the interaction of them with the blood flow. The model is shown in the attached picture.

In my modified model, when the simulation starts it reports

Failed to find consistent initial values.
Last time step is not converged.

Any trick to define the boundary conditions? I've tried composite and assembly geometries with no vail.

Thanks.
Lathi.


hi Lathi Did you solve your problem?I encounter the same error as u did in my FSI model and I dont know how to solve it! whould you please help me? I would be very thankful maral [QUOTE] I was trying to simulate a FSI problem by modifying the COMSOL FSI example, trying to see the same effect presented in the following reference: Zhiyong Li, Simulation of the Interaction between Blood Flow and Atherosclerotic Plaque, Proceedings of the 29th Annual International Conference of the IEEE EMBS Cité Internationale, Lyon, France, August 23-26, 2007. It creates a plaque with cap and core of different Young's moduli, and computes the interaction of them with the blood flow. The model is shown in the attached picture. In my modified model, when the simulation starts it reports Failed to find consistent initial values. Last time step is not converged. Any trick to define the boundary conditions? I've tried composite and assembly geometries with no vail. Thanks. Lathi. [/QUOTE]
Danial Tz
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Posted: 1 decade ago 13 juil. 2010, 10:39 UTC−4

hi Lathi
Did you solve your problem?I encounter the same error as u did in my FSI model and I dont know how to solve it!
whould you please help me?
I would be very thankful
maral





I was trying to simulate a FSI problem by modifying the COMSOL FSI example, trying to see the same effect presented in the following reference:

Zhiyong Li, Simulation of the Interaction between Blood Flow and Atherosclerotic Plaque, Proceedings of the 29th Annual International Conference of the IEEE EMBS Cité Internationale, Lyon, France, August 23-26, 2007.

It creates a plaque with cap and core of different Young's moduli, and computes the interaction of them with the blood flow. The model is shown in the attached picture.

In my modified model, when the simulation starts it reports

Failed to find consistent initial values.
Last time step is not converged.

Any trick to define the boundary conditions? I've tried composite and assembly geometries with no vail.

Thanks.
Lathi.



I assume his problem was the inlet boundary condition for flow. So, instead of entering Umax, you should enter Umax*flc1hs(t-.1,.1), in old comsol notation, or use a step function in Comsol 4.
[QUOTE] hi Lathi Did you solve your problem?I encounter the same error as u did in my FSI model and I dont know how to solve it! whould you please help me? I would be very thankful maral [QUOTE] I was trying to simulate a FSI problem by modifying the COMSOL FSI example, trying to see the same effect presented in the following reference: Zhiyong Li, Simulation of the Interaction between Blood Flow and Atherosclerotic Plaque, Proceedings of the 29th Annual International Conference of the IEEE EMBS Cité Internationale, Lyon, France, August 23-26, 2007. It creates a plaque with cap and core of different Young's moduli, and computes the interaction of them with the blood flow. The model is shown in the attached picture. In my modified model, when the simulation starts it reports Failed to find consistent initial values. Last time step is not converged. Any trick to define the boundary conditions? I've tried composite and assembly geometries with no vail. Thanks. Lathi. [/QUOTE] [/QUOTE] I assume his problem was the inlet boundary condition for flow. So, instead of entering Umax, you should enter Umax*flc1hs(t-.1,.1), in old comsol notation, or use a step function in Comsol 4.
Yajuan Liu
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Posted: 1 decade ago 29 août 2011, 04:00 UTC−4
Hi juan!

I am handling a transient mechnial model. When I change the absolute tolerance from 0.0001 to 0.00001, it shows that :
"Failed to find consistent initial values.
Last time step is not converged."

You say ："If it is a transient analysis try to smooth in time the velocity inlet input multiplyng by a continuos step as
flc1hs(t-0.1,0.1)"

I don't anderstand what does the continuos step exactly mean? And what is the "flc1hs(t-0.1,0.1"?

Thank you in advence!

Best wishes!

Yajuan
Hi juan! I am handling a transient mechnial model. When I change the absolute tolerance from 0.0001 to 0.00001, it shows that : "Failed to find consistent initial values. Last time step is not converged." You say ："If it is a transient analysis try to smooth in time the velocity inlet input multiplyng by a continuos step as flc1hs(t-0.1,0.1)" I don't anderstand what does the continuos step exactly mean? And what is the "flc1hs(t-0.1,0.1"? Thank you in advence! Best wishes! Yajuan
Zhiming Huang
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Posted: 10 years ago 2 sept. 2014, 22:03 UTC−4
The same question with you， how to deal with it
The same question with you， how to deal with it

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