CFD Post - Distance between two walls

m0h · November 1, 2015, 09:28

Hello all,

I am working on an FSI project. There are 2 surfaces in close distance (30-1000µm). I want to create a plot with the normal distance in Z-Direction between these two suraces.

zSurface1(x,y) - zSurface2(x,y) = Plot

The two surfaces would look like the pictures attached. I also added a plot from an external program where you can see how it should look like.

Surface_1.jpg = Smaller Surface http://www.directupload.net/file/d/4...bldgtl_jpg.htm
Surface_2.jpg = Bigger Surface with non overlapping area http://www.directupload.net/file/d/4...olfylx_jpg.htm
both_surfaces = Picture where you can see the overlap http://www.directupload.net/file/d/4...hw95ey_jpg.htm
Plot.png = Result how it should like in CFDPost http://www.directupload.net/file/d/4...un92dz_png.htm

Thank you in advance
m0h

m0h · November 11, 2015, 09:20

Hi,

is there no one who can help with my issue?

m0h

ghorrocks · November 11, 2015, 17:43

I have no idea what you are doing. The images do not make any sense to me, the axis directions are not marked and I do not know where the surfaces are. I think you will find questions like this get ignored until there is enough detail to understand what the question is.

m0h · November 13, 2015, 01:34

Hi Glenn,

als always thanks for your efforts. I like the direct way you say things. Within very less words, everything is clear.
I made a similar simplified example sketch where, at least from my point of view it is easier to understand:

The Wall 1 (orange) is my reference surface. The wall 2 (blue) is the target surface. I want to determine the distance in Z between these two walls as a function of XY. Distance on the left side of border of wall 1 its 27,06mm, in the center its 35mm and on the right side its 42,94mm. I am looking for a plot on Wall 1 where i can see the distance in Z-direction to the other surface.

In this case its simplified because the two surfaces are planar. They can be every 3D shape.

m0h

ghorrocks · November 13, 2015, 05:08

This appears straight forward. The distance between these walls can be expressed analytically from simple geometric calculations. So:

* Define a CEL expression (if in the solver) or a user variable (if in CFD-Post)
* Define the expression to be the analytical function for the distance
* If in the solver the CEL expression will be available as an input to other expressions, or if in the CFD-Post it can be plotted.

m0h · November 16, 2015, 03:35

Hi Glenn,

what i understood from your post is that i shold define an expression with content:

y = 0.06352 * x + 35

But I only showed an simple example where i know the geometry. I am dealing with Mesh Deformation FSI and the surfaces are deformed by thermal and pressure loading. so i dont know the analytical function.

These surfaces can be any shape.

I am looking for someting like
z()@Wall_2 - z()@Wall_1

thanks in advance,
m0h

ghorrocks · November 16, 2015, 05:13

The only way I can think of to do that is to define matching monitor points on the top and bottom walls and use the probe function to get their current locations. Of course this will only return the distance at points you have defined monitor points for.

Alternately you could do a user fortran routine to do this. It is likely this would be quite tricky.

November 1, 2015, 09:28	CFD Post - Distance between two walls	#1
m0h New Member Join Date: Aug 2012 Posts: 20 Rep Power: 13	Hello all, I am working on an FSI project. There are 2 surfaces in close distance (30-1000µm). I want to create a plot with the normal distance in Z-Direction between these two suraces. zSurface1(x,y) - zSurface2(x,y) = Plot The two surfaces would look like the pictures attached. I also added a plot from an external program where you can see how it should look like. Surface_1.jpg = Smaller Surface http://www.directupload.net/file/d/4...bldgtl_jpg.htm Surface_2.jpg = Bigger Surface with non overlapping area http://www.directupload.net/file/d/4...olfylx_jpg.htm both_surfaces = Picture where you can see the overlap http://www.directupload.net/file/d/4...hw95ey_jpg.htm Plot.png = Result how it should like in CFDPost http://www.directupload.net/file/d/4...un92dz_png.htm Thank you in advance m0h

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November 11, 2015, 09:20		#2
m0h New Member Join Date: Aug 2012 Posts: 20 Rep Power: 13	Hi, is there no one who can help with my issue? m0h

November 11, 2015, 17:43		#3
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,728 Rep Power: 143	I have no idea what you are doing. The images do not make any sense to me, the axis directions are not marked and I do not know where the surfaces are. I think you will find questions like this get ignored until there is enough detail to understand what the question is.

November 13, 2015, 01:34		#4
m0h New Member Join Date: Aug 2012 Posts: 20 Rep Power: 13	Hi Glenn, als always thanks for your efforts. I like the direct way you say things. Within very less words, everything is clear. I made a similar simplified example sketch where, at least from my point of view it is easier to understand: The Wall 1 (orange) is my reference surface. The wall 2 (blue) is the target surface. I want to determine the distance in Z between these two walls as a function of XY. Distance on the left side of border of wall 1 its 27,06mm, in the center its 35mm and on the right side its 42,94mm. I am looking for a plot on Wall 1 where i can see the distance in Z-direction to the other surface. In this case its simplified because the two surfaces are planar. They can be every 3D shape. m0h

November 13, 2015, 05:08		#5
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,728 Rep Power: 143	This appears straight forward. The distance between these walls can be expressed analytically from simple geometric calculations. So: * Define a CEL expression (if in the solver) or a user variable (if in CFD-Post) * Define the expression to be the analytical function for the distance * If in the solver the CEL expression will be available as an input to other expressions, or if in the CFD-Post it can be plotted.

November 16, 2015, 03:35		#6
m0h New Member Join Date: Aug 2012 Posts: 20 Rep Power: 13	Hi Glenn, what i understood from your post is that i shold define an expression with content: y = 0.06352 * x + 35 But I only showed an simple example where i know the geometry. I am dealing with Mesh Deformation FSI and the surfaces are deformed by thermal and pressure loading. so i dont know the analytical function. These surfaces can be any shape. I am looking for someting like z()@Wall_2 - z()@Wall_1 thanks in advance, m0h

November 16, 2015, 05:13		#7
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,728 Rep Power: 143	The only way I can think of to do that is to define matching monitor points on the top and bottom walls and use the probe function to get their current locations. Of course this will only return the distance at points you have defined monitor points for. Alternately you could do a user fortran routine to do this. It is likely this would be quite tricky.