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How to calculate average radial concentration vs axial length?

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Geometry: Simple rectangle (cartesian coordinates) width>height
Model: Transport of diluted species - time dependent

I have solved the equivalent of Taylor dispersion in a rectangular channel as a function of time. In order to compare with Taylor's analytical expression, I need to determine the average concentration in the y direction as a function of x for a given time. Using a Cut Line 2D I am able to plot the concentration for all x for a given y position or vise versa, but I cannot figure out how to average the concentration in the y direction for a given time and plot as a function of x.

Therefore, I would be much appreciative if someone could describe step by step how to do this. I have been through every COMSOL manual and cannot find a single description of this type of result manipulation.

2 Replies Last Post 13 apr 2012, 19:17 GMT-4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 17 nov 2011, 07:43 GMT-5
Hi

you have the "Definition - Model Couplings - Linear or general projection" operator to integrate over a line or curve and make a field variable you can access at another spatial position, check the doc

--
Good luck
Ivar
Hi you have the "Definition - Model Couplings - Linear or general projection" operator to integrate over a line or curve and make a field variable you can access at another spatial position, check the doc -- Good luck Ivar

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Posted: 1 decade ago 13 apr 2012, 19:17 GMT-4

Hi

you have the "Definition - Model Couplings - Linear or general projection" operator to integrate over a line or curve and make a field variable you can access at another spatial position, check the doc

--
Good luck
Ivar


Hi Ivar :)

I have the same issue, and I'd love if you could elaborate a little more your answer, because the document doesn't help. I have a square channel with a free and porous media flow, and I want to find the average velocity of the fluid over the length of the channel. Now, I created the Linear projection as you indicated and selected first the domain and the vertices of the source face and the destination face and nothing, then I tried with the boundary, and nothing.
Is there a way of getting the average of each "slide" of a variable per length differential increment so I can plot that average against the lenght coordinate? Please help :)

Thanks a lot :)
[QUOTE] Hi you have the "Definition - Model Couplings - Linear or general projection" operator to integrate over a line or curve and make a field variable you can access at another spatial position, check the doc -- Good luck Ivar [/QUOTE] Hi Ivar :) I have the same issue, and I'd love if you could elaborate a little more your answer, because the document doesn't help. I have a square channel with a free and porous media flow, and I want to find the average velocity of the fluid over the length of the channel. Now, I created the Linear projection as you indicated and selected first the domain and the vertices of the source face and the destination face and nothing, then I tried with the boundary, and nothing. Is there a way of getting the average of each "slide" of a variable per length differential increment so I can plot that average against the lenght coordinate? Please help :) Thanks a lot :)

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