Cross-section average as function of position

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Hi everyone,

I have a simple system where I have a freely flowing tube depositing some concentration into a porous medium surrounding that tube. The tube is straight along a single axis and has regular dimensions.

I would like to calculate (and plot) the cross-sectional average of concentration as a function of length along the pipe (C_avg vs x). I only want data for the pipe, not the surrounding medium. However, I've had some trouble in locating the correct method/function to do this.

Any help would be greatly appreciated! Thank you in advance.

Best, Carl


3 Replies Last Post Jan 27, 2026, 3:43 a.m. EST

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Posted: 7 hours ago Jan 26, 2026, 10:02 p.m. EST

Although I would love to hear what the ideal solution is, I came up with this:

-Make a second study with an auxiliary sweep of a position parameter "xp = range(start,step,end)" -Make a cut line in Results>Datasets>Cut Line 3D and set... x1 = x2 = xp, y1 = y2 = 0, z1 = 0 and z2 = radius_of_tube -Evaluated two line integrals in Results>Derived Values>Line Integration with expressions 2.pi.z.concentration and 2.pi.z. -I divided by the first integral results by the second, resulting in the average along that line (due to my symmetry, this is equivalent to avg of x-section)

Although I would love to hear what the ideal solution is, I came up with this: -Make a second study with an auxiliary sweep of a position parameter "xp = range(start,step,end)" -Make a cut line in Results>Datasets>Cut Line 3D and set... x1 = x2 = xp, y1 = y2 = 0, z1 = 0 and z2 = radius_of_tube -Evaluated two line integrals in Results>Derived Values>Line Integration with expressions 2.pi.z.concentration and 2.pi.z. -I divided by the first integral results by the second, resulting in the average along that line (due to my symmetry, this is equivalent to avg of x-section)

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Posted: 2 hours ago Jan 27, 2026, 3:06 a.m. EST

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Predictable mastery means building habits that make success repeatable, not random. It focuses on clear routines, steady practice, and simple tracking of progress. Instead of chasing luck, people refine small actions every day. Athletes, artists, and leaders all rely on this idea to perform under pressure. Even a [boston mentalist](https://www.predictablemastery.com/) trains the same patterns again and again to deliver reliable outcomes. Over time, skills turn into muscle memory. This approach removes guesswork and builds calm confidence, helping effort translate into results you can trust.

Acculution ApS Certified Consultant

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Posted: 1 hour ago Jan 27, 2026, 3:43 a.m. EST

This sounds like a Projection operator setup: https://doc.comsol.com/5.5/doc/com.comsol.help.comsol/comsol_ref_definitions.12.069.html

-------------------
René Christensen, PhD
Acculution ApS
www.acculution.com
info@acculution.com
This sounds like a Projection operator setup: https://doc.comsol.com/5.5/doc/com.comsol.help.comsol/comsol_ref_definitions.12.069.html

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