Coordinate System for radially growing bubble

[annier]

Axisymmetric Coordinate System and its corresponding solid model for 3D system:
An axisymmetric modeling is defined as a process to analyze a revolved 3D part as a 2D model wherein the part and the loads are axisymmetric. As mentioned in this link, axisymmetric model gives the result as it should be in 3D system.

1. The first figure represents the 2d model used for FEM simulation in Elmer using axisymmetric coordinate system.

figure_1

axisymmetry_2D.png (5.67 KiB) Viewed 2563 times

2. The second figure represents the solid obtained by revolving the same geometry by 90 degrees around OY axis.

figure_2

solid_revolved_around_OY_by_90degrees.png (13.47 KiB) Viewed 2563 times

3. The third figure represents the solid obtained by revolving the same geometry by 180 degrees around OY axis.

figure_3

solid_revolved_around_OY_by_180degrees.png (11.21 KiB) Viewed 2563 times

All the geometries are drawn in Salome 7.4.0.

If the figure_1 (2D) is the geometry for the FEM in elmer under axisymmetric coordinate system for a bubble(sphere) in a liquid/molten metal(defined by a cylindrical medium), what is the actual 3D object-
1) figure_2
2) figure_3
3) solid revolved by 360 degrees around OY?

Update: The answer is that the solid revolved by 360 degrees around the symmetric axis is the 3D solid and sectional views represented by figure_2 and figure_3 or any other revolution angles can be a preprocessing or post processing view to observe the internal structure of a closed solid like sphere or cylinder. In other words, 3) is the answer and figures like those depicted by 1) and 2) [depending upon the users' choices] are used to present the schematic representation of answer 3).

Yours
Anil Kunwar

[annier]

Hi,
The corresponding 3D model for the axisymmetric 2D model (figure_1) in the above post for simulation in Elmer,is a complete sphere surrounded by a cylinder i.e. solid obtained by revolving the 2d R-z plane ( in axisymmetric plane) by 360 degrees. The R,z coordinates of axisymmetric coordinates are mapped with x,y cartesian coordinates when performing a simulation.

In above post, 1) and 2) implying 3) are the answers for the question as, 1) and 2) are the sectional views of solid section in 3D obtained by revolving the r-z plane by 360 degrees around the OY axis.
Similarly,the following figures(figure_4 and figure_5), drawn in Salome 7.4.0 represent the solids revolved around 270 degrees and 315 degrees around the symmetric axis OY plane.

figure_4

solid_revolved_around_OY_axis_by_270degrees.png (38.96 KiB) Viewed 2563 times

figure_5

solid_revolved_around_OY_by_315degrees.png (14.15 KiB) Viewed 2563 times

In context of Elmer, what data should we export from Elmer to visualize the 3D geometry of the corresponding axisymmetric 2d model in postprocessing tools like paraview?

Note:
1. In COMSOL software, what i could understand is that, the postprocessing of axisymmetric coordinate system is made available in 3D by mapping the coordinates and revolving the plane around the axisymmetric axis by 270 degrees for showing the internal structure of the 3D geometry.
2. This link related to the postprocessing of data from OpenFOAM in paraview, mentions that paraview has ability to visualize the axisymmetric simulation in 3D style.

Yours
Anil Kunwar

[annier]

If you do not need to solve the equations in the different coordinate systems but want to visit them for visualization purposes, for example. Then you may use a Solver specific coordinate system with the keyword, e.g.

Code: Select all

   Coordinate Transformation = String "cartesian to cylindrical"

or you could have an initial mesh that is transformed into a cartesian mesh at the time of reading setting in Simulation section

Code: Select all

Coordinate Transformation = String "cylindrical to cartesian"

Can i perform a simulation in cylindrical 2D and visualize it in Cartesian 3D using coordinate transformation?

Yours
Anil Kunwar

[raback]

No. But I think this is supported in Paraview. -Peter