Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

simple model of "inflating a cavity" with a fluid

Please login with a confirmed email address before reporting spam

Hi,

I am attempting a simple 2-D fsi model (what I consider simple, anyway).

I am attaching the model. The intent of the model is to have an inlet of a fluid, and for that to fill (and expand) the cavity. Quite literally like filling a 2-d water balloon. Ultimately what I want to build is a cavity with an inlet that will provide a fluid filling phase where an outlet is closed, and then another phase where the outlet is open, and the inlet is closed, and the walls to squeeze out the fluid. I have defined a solid domain surrounding a fluid domain, and a rectangular opening at the top of the solid domain, which serves as the inlet. As of now, there is not an outlet defined.

I have added the solid domain to the Linear Elastic Model, and inlet, and a couple of fixed constraints (the vertical walls of the inlet which are part of the solid domain).

The error I am getting is "Failed to find consistent initial values", and I am not quite sure what I have left out of the model, or even if COMSOL can solve this situation. Is there anyone that has done a similar kind of simple FSI model, or encountered this kind of error, and if you could provide some insight?

Thanks!


2 Replies Last Post 2011年6月17日 GMT-4 15:53

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 2011年5月14日 GMT-4 11:56
Hi,

I am definitely a COMSOL neophyte, but understanding this kind of a physical interaction is very important to eventually modeling a right ventricle

I am starting to think its because there is not a bounding wall outside of the freely moving boundary - e.g. is this because there is no domain into which the structure can expand?

Hi, I am definitely a COMSOL neophyte, but understanding this kind of a physical interaction is very important to eventually modeling a right ventricle I am starting to think its because there is not a bounding wall outside of the freely moving boundary - e.g. is this because there is no domain into which the structure can expand?

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 2011年6月17日 GMT-4 15:53
Hi.

i have managed some success with this, but backed away from the FSI mod for now. I have upgraded to 4.2.0.179. I have changed the geometry to have an elliptically shaped fluid domain surrounded with a solid (tissue), with an inlet and outlet at different pressures, and have solved the CFD first and then use the output from Solver 1 into the solid mechanics to watch the deformation. Its under pretty large pressure, and the pressure is not a function of time, so the deformation happens quickly, and stays in a steady state. But, it demonstrates what I wanted to do.

I will attach my model for anyone interested in seeing what I did.

I want to be able to do what I am doing in this distinct, but coupled, procedures, using the 2-way coupling offered by FSI. If I get that working I will upload that model. I also want to play with the pressure profiles.

Hi. i have managed some success with this, but backed away from the FSI mod for now. I have upgraded to 4.2.0.179. I have changed the geometry to have an elliptically shaped fluid domain surrounded with a solid (tissue), with an inlet and outlet at different pressures, and have solved the CFD first and then use the output from Solver 1 into the solid mechanics to watch the deformation. Its under pretty large pressure, and the pressure is not a function of time, so the deformation happens quickly, and stays in a steady state. But, it demonstrates what I wanted to do. I will attach my model for anyone interested in seeing what I did. I want to be able to do what I am doing in this distinct, but coupled, procedures, using the 2-way coupling offered by FSI. If I get that working I will upload that model. I also want to play with the pressure profiles.

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.