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Modeling fluid flow
Posted May 20, 2010, 11:33 a.m. EDT Fluid & Heat 4 Replies
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Hello
I am trying to model fluid-structure interaction and keep getting errors. I am modeling fluid flowing out of a channel. The channel is located very close to some other object, so the flow is supposed to interact with this object. I hope I explained the problem well enough to understand it. I am not sure what I am doing wrong but I keep getting these errors :
Error: 6170
Failed to evaluate variable
- Variable: lm7
- Geometry: 1
- Dimension: 3
- Domains: {1}
Failed to evaluate expression
- Expression: lm7
Failed to evaluate expression
- Expression: lm7
Failed to evaluate expression
- Expression: mean(lm7)
Failed to evaluate variable
- Variable: FX_smsld
- Defined as: (((-lm7)*dvol_ale)/dvol)
Failed to evaluate variable
- Variable: FXg_smsld
- Defined as: FX_smsld
Failed to evaluate expression
- Expression: diff(((FXg_smsld*u_test-0)*dvol),u_test)
Does anyone know what this means. I am new to comsol and this is definitely not an easy task for me. Also, if anyone has nay suggestions on how fluid-structure interaction should be modeled, maybe some literature that could help.
Thank you
Marina
I am trying to model fluid-structure interaction and keep getting errors. I am modeling fluid flowing out of a channel. The channel is located very close to some other object, so the flow is supposed to interact with this object. I hope I explained the problem well enough to understand it. I am not sure what I am doing wrong but I keep getting these errors :
Error: 6170
Failed to evaluate variable
- Variable: lm7
- Geometry: 1
- Dimension: 3
- Domains: {1}
Failed to evaluate expression
- Expression: lm7
Failed to evaluate expression
- Expression: lm7
Failed to evaluate expression
- Expression: mean(lm7)
Failed to evaluate variable
- Variable: FX_smsld
- Defined as: (((-lm7)*dvol_ale)/dvol)
Failed to evaluate variable
- Variable: FXg_smsld
- Defined as: FX_smsld
Failed to evaluate expression
- Expression: diff(((FXg_smsld*u_test-0)*dvol),u_test)
Does anyone know what this means. I am new to comsol and this is definitely not an easy task for me. Also, if anyone has nay suggestions on how fluid-structure interaction should be modeled, maybe some literature that could help.
Thank you
Marina
4 Replies Last Post May 20, 2010, 4:00 p.m. EDT
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Posted:
1 decade ago
If you post your model, it would help us more finding the problem.
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Posted:
1 decade ago
I attached the problem. The small cylinder is the channel and the large object is soft tissue. Fluid coming out of the channel is supposed to "interact" with the soft tissue and I need to figure out what is the max stress on the tissue and also the velocity profile of the fluid. Im not even sure if I modeled this correctly. This is my first try.
Thank you very much!!!
Thank you very much!!!
Attachments:
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Posted:
1 decade ago
Looking quickly,
- you have an inlet boundary condition for flow, but you have assigned a structural displacement to the mesh. I think it should have been the other boundary.
- if you have the surrounding of the cylinder fixed, what is the point of having whole the disk? why not just to have the top cap? unless you want to have the disc as a membrane in the flow (like heart valve), which requires a bit different model concept.
Overall, I think you need more elements to complete your model. Why not starting with a simple flow model, and then adding the FSI?
- you have an inlet boundary condition for flow, but you have assigned a structural displacement to the mesh. I think it should have been the other boundary.
- if you have the surrounding of the cylinder fixed, what is the point of having whole the disk? why not just to have the top cap? unless you want to have the disc as a membrane in the flow (like heart valve), which requires a bit different model concept.
Overall, I think you need more elements to complete your model. Why not starting with a simple flow model, and then adding the FSI?
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Posted:
1 decade ago
Thank you, I will try to do what you are saying, im just really lost right now.
Thank you again.
Thank you again.