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Failed to find consistent initial values on FSI simulation

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Lathi Ton

Lathi Ton

September 9, 2009 2:13am UTC

Failed to find consistent initial values on FSI simulation

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.

Attachments:   fsi.JPG  

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Yuanhong Dong

Yuanhong Dong

September 9, 2009 3:22am UTC in response to Lathi Ton

Re: Failed to find consistent initial values on FSI simulation

try a new solver, or u check the scalars u typed, especially the orders of the scalars and constants.

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Juan Anza

Juan Anza

September 12, 2009 9:16am UTC in response to Lathi Ton

Re: Failed to find consistent initial values on FSI simulation

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)

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maral hassani

maral hassani

July 13, 2010 12:35pm UTC in response to Lathi Ton

Re: Failed to find consistent initial values on FSI simulation

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.


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Danial Tz

Danial Tz

July 13, 2010 2:39pm UTC in response to maral hassani

Re: Failed to find consistent initial values on FSI simulation


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.

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Yajuan Liu

Yajuan Liu

August 29, 2011 8:00am UTC in response to Juan Anza

Re: Failed to find consistent initial values on FSI simulation

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

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