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Line Graph on Cut Line 3D at an angle

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Hi,
I have created a Cut Line 3D that is at an angle to the x-axis of my geometry (see attached image). For this Cut Line I would now like to create a 1D plot that uses the Cut Line as the x-axis data and the axial velocity within the pipe as the y-axis data. I can't figure out how to do this as I only seem to be able to use the geometry coordinates (ie x, y or z) and the velocity field components (u, v, w), respectively.
Thank you!
Alexandra


2 Replies Last Post 27.01.2014, 07:06 GMT-5
Phillip COMSOL Employee

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Posted: 1 decade ago 21.01.2014, 08:25 GMT-5
Hi Alexandra,

you can chose the Cut Line as Data Set of a (1D Plot Group) Line Graph. Every Expression on the y-axis will be evaluated on the corresponding point of the Cut Line (x-axis).

The second part of your question is more challenging. As you mention, the velocity components are Cartesian, but your geometry is curved, so the direction of the axial vector is a function of the position in the pipe.

You could try this: “Curvilinear Coordinates” is a physics mode that you can add to your model under Mathematics -> Curvilinear Coordinates. Add “Flow Method” domain to your geometry and Inlets and Outlets to your respective in- and outlet. The Curvilinear Coordinates are calculated just as other physics. As result, you will receive the axial vector field inside of the pipe. Now you can get the axial velocity component easily by multiplying the velocity field and curvilinear field.

Good luck with your model.

--
Best Regards
Phillip
Hi Alexandra, you can chose the Cut Line as Data Set of a (1D Plot Group) Line Graph. Every Expression on the y-axis will be evaluated on the corresponding point of the Cut Line (x-axis). The second part of your question is more challenging. As you mention, the velocity components are Cartesian, but your geometry is curved, so the direction of the axial vector is a function of the position in the pipe. You could try this: “Curvilinear Coordinates” is a physics mode that you can add to your model under Mathematics -> Curvilinear Coordinates. Add “Flow Method” domain to your geometry and Inlets and Outlets to your respective in- and outlet. The Curvilinear Coordinates are calculated just as other physics. As result, you will receive the axial vector field inside of the pipe. Now you can get the axial velocity component easily by multiplying the velocity field and curvilinear field. Good luck with your model. -- Best Regards Phillip

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Posted: 1 decade ago 27.01.2014, 07:06 GMT-5
Hi Phillip,

your suggestion worked perfectly, thanks a lot!

Alexandra
Hi Phillip, your suggestion worked perfectly, thanks a lot! Alexandra

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