Edge or Nodal element

Jerome Teoh

Hello there,

What is the difference between an edge element and a nodal element in FLux, and when should I use one over the other?

 Is there any scenario that the edge element formulation can solve but not the nodal element? vice and versa

  

Thanks,

 Jerome.

Letizia_Ferrara

Hello Jerome,

In Steady State AC Magnetic coupled with Transient Thermal 3D application, if you have regions that is made of ceramics, rubber, you can simply define them as "air or vacuum region" . If you choose inactive the magnetic equation will not solve in these region.

For the convection, if you don't assign it to some faces, the solver considers just the thermal conduction between solids (air included); so if you have air around the device.
Different is when you use just the thermal application, because you can avoid to have the air around, so if you don't assign some convection condition is like to have an adiabatic BC at these faces.

About the edge elements, if you have solid conductors in the model, this formulation is automatically taken into account for "automatic formulation" that you have set by default in the application definition.

Ensure that, when you ask to Flux to solve some quantities inside the volumes, you had already defined the properties of the physic involved in each materials tab. Otherwise Flux should alert you with a message.

I hope this could help.

Best regards,

 

Letizia

Mohammed Elamin_22169

Hi Jerome, 

I hope the the page below from the help give you some insight. 

https://2022.help.altair.com/2022/flux/Flux/Help/english/UserGuide/English/topics/CalculParElementsFinisLesFonctionsDapproximation.htm

Thanks, 

Jerome Teoh

Not quite understand yet, so,

If you implment meshed coil (solid conductor).

it need to be selecting to use the edge approximation?

And you can using either option if using the non-meshed coil?

Last, the nodal and edge formulation will only affected the electrical conductors?

Not other attributes in the model, for example I will have a ceramic blocks in my model that facilitate the heat transfer of my design?

 

 

Thanks,

Jerome.

Jerome Teoh

Mohammed,

I have one more extra question as well.

• For Steady State AC Magnetic coupled with Transient Thermal 3D application, if I have regions that is made of ceramics, rubber. What can I define for the magetic property? Should I just assume relative permeability with value of 1, then checking the magnetic definition as 'magnetic non conducting region (or dielectric)' in the volume region, or I should not need to define magnetic property, and putting inactive region?

Thanks,

Jerome.

Mohammed Elamin_22169

Jerome Teoh said:

Not quite understand yet, so,

If you implment meshed coil (solid conductor).

it need to be selecting to use the edge approximation?

And you can using either option if using the non-meshed coil?

Last, the nodal and edge formulation will only affected the electrical conductors?

Not other attributes in the model, for example I will have a ceramic blocks in my model that facilitate the heat transfer of my design?

 

 

Thanks,

Jerome.

Hi Jerome, 

The selection of edge or nodal formulation is only for solid conductor region (eddy current computation), all other region will have nodal approximation and it will not be affected by this choice. When you use a solid conductor region (either for coil or the working piece), Flux by default select edge formulation, unless you force this through the application to be nodal. which is possible, but you should be careful with the results. 

There is a case mentioned which will require an edge formulation always which is "presence of induced currents tangent to the device edges. These edges are the edges of the inside corners of the device". 

Thanks, 

 

Mohammed Elamin_22169

Jerome Teoh said:

Mohammed,

I have one more extra question as well.

• For Steady State AC Magnetic coupled with Transient Thermal 3D application, if I have regions that is made of ceramics, rubber. What can I define for the magetic property? Should I just assume relative permeability with value of 1, then checking the magnetic definition as 'magnetic non conducting region (or dielectric)' in the volume region, or I should not need to define magnetic property, and putting inactive region?

Thanks,

Jerome.

Yes, this should works. as you can't define the magnetic part as "Air or vacuum region" for thermal conducting material.  

Letizia_Ferrara

Hello Jerome,

In Steady State AC Magnetic coupled with Transient Thermal 3D application, if you have regions that is made of ceramics, rubber, you can simply define them as "air or vacuum region" . If you choose inactive the magnetic equation will not solve in these region.

For the convection, if you don't assign it to some faces, the solver considers just the thermal conduction between solids (air included); so if you have air around the device.
Different is when you use just the thermal application, because you can avoid to have the air around, so if you don't assign some convection condition is like to have an adiabatic BC at these faces.

About the edge elements, if you have solid conductors in the model, this formulation is automatically taken into account for "automatic formulation" that you have set by default in the application definition.

Ensure that, when you ask to Flux to solve some quantities inside the volumes, you had already defined the properties of the physic involved in each materials tab. Otherwise Flux should alert you with a message.

I hope this could help.

Best regards,

 

Letizia