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Geometry within a Geometry
Posted Jun 20, 2010, 12:45 p.m. EDT 3 Replies
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Hi,
I have a geometry within a geometry, as shown in my screenshot attached.
The problem I am facing is that if I "subtract" the inner geometry from the outer one (create a composite), then I can describe the internal boundary conditions as I wish (electroosmotic walls), but I no longer have inner and outer subdomains which can be describe independantly, for example, the inner channel sub-domain needs to be different to the outer sub-domain.
If I create a "union" composite then I have the two independant sub-domains, but I cannot sufficiently describe the inner boundary conditions because now these are internal boundaries and as such feature a limited range of conditions.
Any Thoughts or suggestions?
Regards,
Tom
I have a geometry within a geometry, as shown in my screenshot attached.
The problem I am facing is that if I "subtract" the inner geometry from the outer one (create a composite), then I can describe the internal boundary conditions as I wish (electroosmotic walls), but I no longer have inner and outer subdomains which can be describe independantly, for example, the inner channel sub-domain needs to be different to the outer sub-domain.
If I create a "union" composite then I have the two independant sub-domains, but I cannot sufficiently describe the inner boundary conditions because now these are internal boundaries and as such feature a limited range of conditions.
Any Thoughts or suggestions?
Regards,
Tom
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3 Replies Last Post Jun 21, 2010, 8:23 a.m. EDT
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Posted:
1 decade ago
Hi
I'm not sure I have understood your issue there, but you seem to have added three rectangles, that overlap in the common region. This overlap can give problems I understand when you use union. But you can draw this better, I beleive, by using a 2D drawing and then extruding it into the 3D geometry. THere are different ways, adding in lines and grouping them, or making rectangles and splitting them to delete unwanted small line and add a few then to sew and knit it together
Hope this helps, not sure its really your issue
Anyhow, have fun Comsoling
Ivar
I'm not sure I have understood your issue there, but you seem to have added three rectangles, that overlap in the common region. This overlap can give problems I understand when you use union. But you can draw this better, I beleive, by using a 2D drawing and then extruding it into the 3D geometry. THere are different ways, adding in lines and grouping them, or making rectangles and splitting them to delete unwanted small line and add a few then to sew and knit it together
Hope this helps, not sure its really your issue
Anyhow, have fun Comsoling
Ivar
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Posted:
1 decade ago
Hi Ivar,
I appreciate your recommendations regarding the geometry.
I will try to be clearer with describing my problem.
I am modelling a microfluidic channel. The fluidic channels are modelled using the inner geometry. The outer geometry is a small surrounding section of the reactor material.
The surrounding material (outer geometry) sub-domain needs to be described differently to the inner sub-domain geometry, plus, I need to be able to describe the inner walls as an electroomostic velocity.
The problem is if I subtract the inner from the outer then I reduce the problem to a single sub-domain, but I can set the boundary conditions as an electroosmotic velocity because all the boundary conditions for the application mode are available to me.
However, if I create a union between the outer and inner geometries then I achieve two independant sub-domains, but the inner boundary conditions are limited (velocity, continuity or wall) - because now the inner geometry is treated as an interior boundary.
I don't know how to arrange the model geometry to achieve a model which can ultilise all the application mode boundary conditions while keeping independant sub-domains?
Any clearer?
Thank you.
Regards,
Tom
I appreciate your recommendations regarding the geometry.
I will try to be clearer with describing my problem.
I am modelling a microfluidic channel. The fluidic channels are modelled using the inner geometry. The outer geometry is a small surrounding section of the reactor material.
The surrounding material (outer geometry) sub-domain needs to be described differently to the inner sub-domain geometry, plus, I need to be able to describe the inner walls as an electroomostic velocity.
The problem is if I subtract the inner from the outer then I reduce the problem to a single sub-domain, but I can set the boundary conditions as an electroosmotic velocity because all the boundary conditions for the application mode are available to me.
However, if I create a union between the outer and inner geometries then I achieve two independant sub-domains, but the inner boundary conditions are limited (velocity, continuity or wall) - because now the inner geometry is treated as an interior boundary.
I don't know how to arrange the model geometry to achieve a model which can ultilise all the application mode boundary conditions while keeping independant sub-domains?
Any clearer?
Thank you.
Regards,
Tom
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Posted:
1 decade ago
Hi Tom,
To my understanding if you have internal boundaries it means that you have 1 physics over both domains (e.g. convection). One thing to you can do is to separate 1 physics into 2 similar physics defined on each domain. This way you will have normal boundaries. Just you have to make sure there is continuity on bc's (or other bc).
Hope I got you correct and above method actually works.
To my understanding if you have internal boundaries it means that you have 1 physics over both domains (e.g. convection). One thing to you can do is to separate 1 physics into 2 similar physics defined on each domain. This way you will have normal boundaries. Just you have to make sure there is continuity on bc's (or other bc).
Hope I got you correct and above method actually works.