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Simulation fails when I add heat transfer physics
Posted 07.04.2016, 19:33 GMT-4 Heat Transfer & Phase Change, Geometry, Modeling Tools & Definitions, Parameters, Variables, & Functions, Studies & Solvers Version 5.0 2 Replies
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Good morning,
I'm a student and I'm trying to model on Comsol an implantable fetal pacemaker (PM). I modeled the system with a corkskrew (helix) that represents the working electrode of the PM; then, I modeled the body of the PM with two cylinders linked to the helix mentioned above (one of the two is used as the ground of the PM). Finally, to simulate the environement of the PM (heart tissue, blood), I added two larger cylinders who enfold the PM.
When I run the simulation (stationary study) using just the physics "electric current", it works without any problem: I succeed to simulate the voltage and the current density reached in the system.
As I try to add a second physics (Heat transfer in solids or Bioheat transfer) the simulation fails and I always got the same message "Failed to find a solution. Segregated group 2. Out of memory during LU factorization".
Now, even if I don't have such a great experience with comsol, I don't think that my model is too complex to run a simulation with two physics; however, I still can't get the solution of this problem.
If anybody could give me any tip, I'd appreciate it.
Thank you very much!
P.s. I attach some photo of the model in the case somebody was so kind to help me.
I'm a student and I'm trying to model on Comsol an implantable fetal pacemaker (PM). I modeled the system with a corkskrew (helix) that represents the working electrode of the PM; then, I modeled the body of the PM with two cylinders linked to the helix mentioned above (one of the two is used as the ground of the PM). Finally, to simulate the environement of the PM (heart tissue, blood), I added two larger cylinders who enfold the PM.
When I run the simulation (stationary study) using just the physics "electric current", it works without any problem: I succeed to simulate the voltage and the current density reached in the system.
As I try to add a second physics (Heat transfer in solids or Bioheat transfer) the simulation fails and I always got the same message "Failed to find a solution. Segregated group 2. Out of memory during LU factorization".
Now, even if I don't have such a great experience with comsol, I don't think that my model is too complex to run a simulation with two physics; however, I still can't get the solution of this problem.
If anybody could give me any tip, I'd appreciate it.
Thank you very much!
P.s. I attach some photo of the model in the case somebody was so kind to help me.
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2 Replies Last Post 14.04.2016, 04:08 GMT-4
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Posted:
9 years ago
Hi,
there's an other post regarding your problem from 2009
www.comsol.com/community/forums/general/thread/581/
Running out of memory could just mean that. Your System does not have enough RAM. Either because you're using a 32 bit System or that you simply don't have that much RAM.
If you're running a simulation with 2 connected Physics the resulting matrix ist larger and has much more non-null entries, just because the variables are stronger interconnected with each other.
The solver has to handle a bigger matrix with more non-zero entries and needs therefore more RAM and time do finish the LU factorization.
Well you're using a segregated solver and not a fully coupled one. So the physics should be solved independently from each other. So I don't know whether the system matrix is getting bigger or less sparse. But it still needs more RAM to store the solution from the other physics I think.
Maybe you should post more details on the discretization, mesh and solver settings you're using.
there's an other post regarding your problem from 2009
www.comsol.com/community/forums/general/thread/581/
Running out of memory could just mean that. Your System does not have enough RAM. Either because you're using a 32 bit System or that you simply don't have that much RAM.
If you're running a simulation with 2 connected Physics the resulting matrix ist larger and has much more non-null entries, just because the variables are stronger interconnected with each other.
The solver has to handle a bigger matrix with more non-zero entries and needs therefore more RAM and time do finish the LU factorization.
Well you're using a segregated solver and not a fully coupled one. So the physics should be solved independently from each other. So I don't know whether the system matrix is getting bigger or less sparse. But it still needs more RAM to store the solution from the other physics I think.
Maybe you should post more details on the discretization, mesh and solver settings you're using.
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Posted:
9 years ago
Hi, thanks for your answer.
I got the solution of my problem just few days ago, by myself: I was using Comsol 5.0 on Windows 10, and apparently there were some problems of compatibility.
Now I'm using Comsol 5.2 and it's OK.
I got the solution of my problem just few days ago, by myself: I was using Comsol 5.0 on Windows 10, and apparently there were some problems of compatibility.
Now I'm using Comsol 5.2 and it's OK.