Menu

Discussion Forum

New Discussion
Filter

Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Incorrect calculation of interpolation fuction in cylidrical coordinate system (3D)

Posted Oct 30, 2013, 7:44 p.m. EDT Geometry, Parameters, Variables, & Functions Version 4.2a, Version 4.3, Version 4.3a, Version 4.3b 4 Replies

Mikhail Polous
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Hello! Need your help!
Sorry for my bad English.

There is 3D model. Heat transfer module. I need to set Heat Source depended on "phi"-coordinate.
I defined a cylindrical coordinate system (sys2) with default settings, also defined an interpolation function for heat source (int3) - table f=f(t), where t [rad], f [W]. Then in Heat Transfer in Solids --> Coordinate System Selection --> Cylindrical System 2 (sys2), then I created Heat Source with Total power = int3(sys2.phi).
In result i have incorrect calculation of Heat Source (see attached picture).
What have I done wrong?

Attachments:

4 Replies Last Post Nov 5, 2013, 9:30 a.m. EST
Jens Krause
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Oct 31, 2013, 4:21 a.m. EDT
Helllo Mikail,

Does the angle inside Comsol lie in the interval [0,2*pi]? Or perhaps in [-pi,pi]? The latter would explain your result.
Have you tried making the piecewise function periodic?

Regards

Jens
Helllo Mikail, Does the angle inside Comsol lie in the interval [0,2*pi]? Or perhaps in [-pi,pi]? The latter would explain your result. Have you tried making the piecewise function periodic? Regards Jens
Mikhail Polous
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Oct 31, 2013, 10:01 a.m. EDT

Helllo Mikail,

Does the angle inside Comsol lie in the interval [0,2*pi]? Or perhaps in [-pi,pi]? The latter would explain your result.
Have you tried making the piecewise function periodic?

Regards

Jens


Interesting idea about [-pi,pi]! I will try to use this angle. Thx :)
How can I make the piecewise function periodic?
[QUOTE] Helllo Mikail, Does the angle inside Comsol lie in the interval [0,2*pi]? Or perhaps in [-pi,pi]? The latter would explain your result. Have you tried making the piecewise function periodic? Regards Jens [/QUOTE] Interesting idea about [-pi,pi]! I will try to use this angle. Thx :) How can I make the piecewise function periodic?
Jens Krause
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Nov 4, 2013, 2:20 a.m. EST
The combobox for extrapoation has an item "periodic"

Regards

Jens
The combobox for extrapoation has an item "periodic" Regards Jens
Magnus Ringh COMSOL Employee

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Nov 5, 2013, 9:30 a.m. EST
Hi,

The interval for the azimuthal angle phi in Cylindrical System and Spherical System coordinate systems is [-pi, pi]. The interval for the angle of inclination theta in Spherical System coordinate systems is [0, pi].

Best regards,
Magnus Ringh, COMSOL
Hi, The interval for the azimuthal angle phi in Cylindrical System and Spherical System coordinate systems is [-pi, pi]. The interval for the angle of inclination theta in Spherical System coordinate systems is [0, pi]. Best regards, Magnus Ringh, COMSOL

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.

Suggested Content