# Discussion Forum

## Integration in a custom coordinate system.

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I have a pipe geometry aligned with the z axis shifted in x and y. I want to calculate the men fluid temperature through the pipe. I use the integration operator with the spatial at expression (through a variable). The syntaxis i try is like: integrate(integrate(comp1.at3(sys2.r,sys2.phi,sys2.a,Tw),sys2.r,0,ra),sys2.phi,-pi,pi). The frame of the sys2 cylindrical coordinate system is spatial. The axis directions are checked and are correct. I can integrate if the pipe is made as an axisymmetric study but is the study is a 3D component, the integral fails. If i build a square geometry and evaluate it in the same way - using the integral syntax, i get the right result (using the default coordinate system).

It must be something of the coordinate system interpretation.

2 Replies Last Post Oct 17, 2020, 11:24 PM EDT

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Posted: 2 weeks ago

This is the program - very simple. Can you please help. I am running out of time for my work.

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Posted: 2 weeks ago
Updated: 2 weeks ago
1. When I want to compute an average of a quantity that is available in post-processing, I usually define a probe. Under Component 1, choose definitions, right-click and select Probes, then Domain Probe. The default is average. Probes are usually pretty easy to use. You don't have to apply specific integration operators or deal with offset coordinate systems to merely compute averages, in most cases.
2. By the way, your model (case.mph) seems to be a "laminar flow" model with physics that doesn't seem to involve temperature?! So, I'm not sure what you'll achieve by computing a mean temperature. Good luck.